we also have the graph of who invited who, and who was given extra invites, and so on, so i can very quickly check things like "did this person i gave invites to invite people who got reported for a bunch of stuff"

I always look at peoples profiles and do a gut check. If the person seems genuine, engaging with people in good faith, having fun with others, and just generally contributing positively to culture I tend to give them invites (if i have time!)
I probably spend two hours a day giving invites