About using "only" with present perfect

I have seen this sentence in a status from one of my facebook friends. It doesn't sound right to me.

We have only left the city for the day.

I think that it should be something like:

We have left the city for only a day (just for a day).

Which one is correct and what is the usage of only with present perfect? I consider sentences like

We have only seen a few of the sights of this marvelous city.

to be correct, but the above sentence just doesn't sound correct for me.

Careful (not to say pedantic) speakers place 'only' directly in front of the word or phrase it qualifies. So they would say: "I drink only water." The claim is that saying: "I only drink water" could be interpreted as meaning: "Drinking is the only thing I do with water, not washing in it or playing with it, etc."

In theory there may indeed be cases where the placement of 'only' is a source of ambiguity. In practice, however, it is unlikely that anyone would be confused, particularly in spoken language where intonation contributes to meaning.

"We have only seen a few of the sights of this marvelous city" sounds perfectly natural to me, a native speaker. In fact Google returns 3 times as many hits for "I have only seen ..." as for "I have seen only ... ".

As an aside, the sentences are in the present, not past, perfect. But the tense of the statement is irrelevant to considerations of where 'only' should be placed.

The placement of only has nothing to do with the present perfect construction, but with the placement of the focus NP that only binds. Here's what McCawley (p.68) says about it:

There are a number of words in English (only, even, too, also) that are associated with a focus: an item that is implicitly contrasted with other items, as in John drinks only beer, where only serves to contrast beer with such other items as wine, vodka, and so on. Only usually precedes its focus, but need not immediately precede it; for example, John only drinks beer can be intrepreted with beer as focus even though only is separated from it by drinks.

Basically, the rule is that only must bind some focussed item (word, phrase, or clause) that comes after it. This focus must have primary stress (He only drinks beer).

Only may appear

• either immediately before the focus,
• or immediately before the first word of a constituent that contains the focus.

The reason why John only drinks beer can be interpreted with beer as focus is because drinks is the first word in a Verb Phrase (drinks beer) that contains beer. It can also be interpreted with drinks as focus (as opposed to, say, brews or sells), or with the whole VP drinks beer as focus (as opposed to, say, smokes pot or gambles).

We have only left the city for the day is the normal way of saying the speaker and the speaker’s companions are absent from the city for the day and for no longer. We have left the city for only a day means the same, but is probably found less frequently.