Saw a GC member attempting this today. Peklz had it under control.
And for one other specific one which was being discussed... bunny hopping. I don't think it's an exploit, it doesn't speed you up at all, and as long as it's not a script it's not illegal in leagues.
it definitely does speed you up; from CT spawn, vovik can get to the area above the pit in dust2 before T's can look through double doors and see who crosses, so watch out for that area from now on
i think exploits are on a case by case basis, such as planting in the fountain of goldfish on inferno in hopes that the goldfish will block the defuse