Name on a list, sure, fine. Pretty standard practice in big office buildings.

Running the guest list against some database of banned names, not so standard.

One reason it's not standard is that properly operating a list of banned names is very difficult, for the reason pointed out here in this post.

I didn't get this context from the post when I read it first - I guess this begs the question - was this a former employee of yelp or was it a true mixup?

It's a student, definitely not a former yelp employee or homeless person.

I'm a crazy homeless person, my name is Adam Smith, nice to meet you. Or was it John Brown? Do they check government-issued ID? I'm visiting from BC or Ontario, you think they could recognize a fake ID?

I think the logic is that if you have successfully guessed a name that is good enough for them - remember - we are talking about people who are literally walking in off the street - they aren't trying to 'game the system' - they might not even know where the hell they are

some places ask for ids - but really a lot of places you just need to have the name - that's all