Today i got ban in one of my 5 accounts, yesterday i was leveling a low lvl alt, i was only using custom teleport, and sometimes speed hack (50%), i was in queensdale and is very possible that ive got reported but i will not put my bets in it, i always take care how to act if ppl is possible to be around, ive lvled many alts there and first time i got a ban.
My best guess about what probably has happened is: i was completing many events very fast and then ive hit some kind of anet exploit protection, the result is when its happens you start get very low xp per event BUT ive hit that protection MANY times before and never had issues till now, probably now you get flagged and someone come to check your account and then BAN.
In my all others accounts ive using every day speed hack (50%), click to teleport and wall hack sometimes, custom teleports a lot to farm nodes and right now that accounts are ok, maybe queued to a account check and BAN who knows lol.