my answer would be relatively strict...
but i think my kids got through because they were with us...
the truth is, my kids don't drink alcohol, but it was just the principle of not having to wear the hated wristbands (identifying you as under 21)...
in any case, the drinking age in the country where we live is 18 and both of them are over that, so it's sort of silly....but as i said, they don't drink anyway..
but what happened was as follows:
my daughter will be 21 in October....but she has a backwards date on her drivers license (since we don't live in america the date shows the day first, then the month)...so due to the reverse order, it looked as though she was 21 to any american who doesn't know that everywhere else in the world, dates are reversed....
that was in the case of my 20 year old, almost 21 year old daughter.....when they carded her, her drivers license looked as if she's 21 years old and that's what they believed.....perhaps if they read this post, they'll know better in the future....doesn't matter, since the next time she's there, she'll actually be 21.....
as for my 18 year old son, he looks about 30 (he's very very very tall, with a very heavy beard)....they didn't ask him for an ID......that was the funniest thing of all.....and drove my daughter crazy...
not only did they not ask for an ID, they didn't even ask him how old he is and he's only 18....they just stamped his hand and went on to the next person.......
the main thing that it was useful for was to get them into mannequins (and jelly rolls on the boardwalk)....in the end, mannequins was boring....
in fact, all of the music clubs in pleasure island were boring....no one at all was dancing.....my kids are only interested in dancing, not sitting around boozing and listening to music....that's not what it's like at dance clubs at home....they were very disappointed that no one was dancing and so we left (we first went into every single club to check it out)..
it's possible that much later at night people do dance, but at about 11 when we were there, no one was dancing....
but anyway, to answer your question, they're relatively strict, but there are loopholes.....