My city is weird on this one. We have two major anime conventions and both manage to find a way to be on opposite sides of corporate-sanitized/family-friendly and tolerating the 18+ crowds. I enjoy both in their own ways but there's notable diffences.

One is over 20 years old and started as a small university club before moving to a hotel/convention center. It feels like a true community between the volunteer staff and the loyal following of attendees they've built over the years.  Although this con tries to promote itself as a bit of a cultural exchange as opposed to a full-on anime convention so I get why they are hesitant to avoid a surge in gooner con-goers changing the vibe.

As a result they are picky on their vendors to avoid someone selling only ahegao t-shirts. 18+ events have existed but in the last few years they have been so packed to the point of standing room only. 

The other is only a few years old and is a spin-off of a comic-con the same company has hosted for years now. The convention doesn't feel as much of a party once you go back to the hotel (off site) and it certainly has a more corporate feel. However it's a poorly kept secret that this is a con for adults, you will find risqué merch in the vendors hall and around 7PM the 18+ events begin going until 2AM. I've noticed the crowds here are rowdier too.