It might've been that you had a friendly vibe. You looked like someone who wouldn't cause a scene, so it'd be safer to mess with you. Add a healthy dose of Halloween anonymity to thrill seeking party girls, and you getting very unlucky.
I'm sorry that happened. Sexual assault is fucked up, no matter who is involved.
Oh I don't mind, I actually have an open everyone gets one squeeze policy, hard to communicate that though. I worked hard on that thing and from my perspective it's not a strictly sexual thing.
That said you are right and I don't encourage people to randomly grab butts out there. Actually don't touch people at all without good reason. But if you do run into me specifically and you can confirm its me, feel free to give it a squeeze, I consent.