Isn't the current punishment scale :
1st offense warning.
2nd offense 1 week bans from all kind of games.
3rd offense, up to admin for severe punishment.
At least that is what happened to the last deadbeater i saw reported 3 times ...
I'd like to add, it seems most speed players don't know deadbeating is forbidden. Maybe a mass pm to remind everyone that deadbeated is forbidden EVEN in speed game, and that the punishment for repeated deadbeating is a ban would help.