BJJ Coffee Drinker said: ↑
Some of the guys coming in used to be paying members, always came to class late, only rolled and never di technique. They eventually stopped their membership, still come to our open mat (no mat fee) and I noticed they basically try and hit up all the other free open mats in town
That started to bother me
To prevent this, my school requires you to have some kind of affiliation or endorsement before you can attend an open mat. We have people occasionally in town for work and they ask to drop in. My coach takes this seriously enough that if the only available day they can come is an open mat day, my coach always asks where they train and calls their instructor. Sometimes we have people show up from out of town without calling first and he has to make a judgement call (typically if they are brown belt or up he allows it), but this system seems to work well for us.