Is "including but not limited to" a redundant phrase?

I would agree that "including" definitely carries the implication of "not limited to"; however, I think this redundant phrasing is simply used in order to emphasize the fact that what follows is not intended to be a complete list.

I think the point of this common bit of ‘legalese’ is that in case anyone should assume that including does mean ‘limited to’ they have no recourse to claim they were misled by believing the list in question was a complete list.

Usually (and especially in law) you include the phrase "but not limited to" to prevent ejusdem generis. For example, consider this phrase:

As used in this statute, "vehicles" shall mean powered vehicles including cars, buses, recreational vehicles, and trucks.

In this case, one can make an argument that airplanes and off-road dirt bikes are not included. All of the examples are highway vehicles that transport people and cargo.

By contrast, if it specifically said, "but not limited to", that would indicate that whole categories of items were not reflected in the examples. In that case, you shouldn't infer that it wasn't meant to include things like airplanes and boats. You'd have to look at the rest of the statute to see if it made sense to include those things.

There is not really anything implying that "including" does not also mean "but not limited to", unless you specify by saying "including but limited to".

I think it is redundant and actually looks quite ugly with the compulsory use of this phrase in for example EULAs and similar documents, but lawyers will probably keep using it, "just to be safe".