At the beginning of Final Fantasy VII, how did Aeris have access to the top level of Midgar?

I, like many, LOVED Final Fantasy VII on it's release and I've played through it a couple times. It wasn't until a recent playthrough of the original demo disc that I realized that the "flower girl" is on the top level of Midgar! I never noticed this because it's Midgar at night and it still has that same dark and dingy feel as the lower level.

Later when Aeris finds Cloud in the church, we learn that the Turks had been pursuing her for practically her entire life. This matters because we learn from Jess that if you are going to the top level of Midgar, the train scans the ID badges of all individuals at certain check-points. If someone is without an ID badge, or if they are on a hazardous persons list, the sirens will go off and Midgar police will apprehend the criminal.

Aeris is not a criminal but she couldn't have an ID badge because, if she did, she could easily be identified as the "ancient" that she is? Reno and the other Turks could then easily apprehend her.

Of course Barret, Cloud and the rest of Avalanche crew had fake IDs which worked well enough at least twice on both the trip up to the top level of Midgar to blow up the first reactor, as well as on the trip home to the lower level of Midgar. However, I seem to recall that these IDs were either expensive or hard to come by, so I doubt Aeris could have had a fake ID.

So... How did she get to the top level of Midgar?

2020 UPDATE

If this is addressed in Final Fantasy VII Remake, I am willing to consider that a better and proper answer, applicable to the original source material.

If we accept

• The only way between the top and bottom levels of Midgar is via train (assuming that staircases would be too heavily guarded for even Avalanche to try to take)
• Aeris would have to commute between lower / upper levels for work on this train
• The only way to ride the train is with a valid id card
• Aeris hasn't been arrested

Then ipso facto Aeris must have a "valid" ID card.

Why is this so hard to believe? There is no reason to suspect that she must have a valid ID card in her name or that the Turks even know what ID card she is using, so short of them sorting through every single commuter systematically there is no way to pin her down.

So, how did she get this ID card? Apart from the short dialog in the train, we know nothing about them. We do know they can be forged, and that Avalanche would rather forge enough cards for their entire crew than just steal some from drunk/asleep people on a train. Maybe this is because in their self-righteous nature they don't want other people to get in trouble for not having an ID card, or maybe ID cards aren't that hard to forge. Does this mean that Aeris could get a forged ID card? Probably. She is familiar enough with the characters in the slums (for example, that guy who are sick), and she is one tough cookie (I mean, she hangs out in a slum infested with HellHouses), so she is probably savvy enough to get her hands on a card. Hell, she's worldly enough not to bat an eye when it comes time to help get Cloud ready for Don Corneo.

But this doesn't mean she has a forged ID card. Let's look at this other scenario (spoilers ahoy! I'm going to try to not use anything other than FFVII as canon): Aeris is 7 when her mother breaks out of Shinra HQ with her, and knowing her death is near, passes her off to a woman who is waiting for her husband to get back from the Wutai War. Now, Shinra knows the Ancients under their control have escaped, and they would definitely be looking for them. But, Aeris and her mother were able to get to Sector 7 without being detected, which means that the ID card system probably didn't exist yet. So, some time in the next 15 years, Aeris (and maybe her adopted mother) probably went through the regular legal mumbo jumbo of getting an ID card. It doesn't really matter that she might not be able to prove her birthplace or lineage, as during Aeris's age of 7 and 16, the Wutai War was going on and creating refugees; she is also from the slums, so there is no reason that they would even bother with having some kind of accurate census to base that kind of information off of. So, one day, a bright-eyed kid walks into the equivalent of a DMV, lines up with a bunch of other slum trash and wants to get an ID card so she can ride the train up to the land of opportunity. The bored clerk (even if there was a clerk. It could just have been a machine) looks at her and says "Do you have the registration fee?", takes her cash, maybe a bribe, takes a photo and registers her under the name of Useless McGetsStabbedInTheBack.

Turks is watching Aerith as a last tribute for Zack (because Cissnei and Tseng). They only try "capture" her when President Shinra issuing the order (they are not tried really hard). Shinra is not suspicious of them because he think as an Ancient , Aerith have some kind of power that make her able to defeat Turks he sent. So it's easy for Turks agent to looks another way when they see her. And only a few people know about her identity as Ancient, so for other Shinra Employee she is just another flower seller. But everything changed when Rufus started taking over Promised Land Project from his old man. or because Aerith got involved with terrorist group (Avalanche)

For ID card,they never removed her privilage for when she is working for Shinra with Zack.She often visiting Shinra with Zack before Promised Land planned.

In Layman terms, Aerith can go to Upper Plate because Tseng as the leader of Turks have a close relationship with Zack (Aerith's Boyfriend),Cissnei (Zack's Friend) and Aerith (His Friend/love interest(?)) and have final say when to capture Aerith. Only after Aerith got involved with Avalanche (He have a really bad experience with them in Before Crisis) he started to following Shinra order to capture her.