Wait, you made it so people can by-pass the nobuildbot file?
If so, forget you.
Right now, buildbot works like a super fast player building. It isn't easy to test whether a client is botting or not. If you want to specify exactly where you draw the line between building fast and botting, I could make something for you. However, if I make a limit on how fast people can plant bricks, then that will mess up regular people that use the hold-enter-key-and-move-brick method. If you want to filter how far people can shift bricks, it will mess up super-shift.
Also: Any options would almost certainly also break macros long before it affected BuildBot.
Really, the bad thing about buildbot is that it is a huge temptation to spam, saying "hey i gawt dis cul mod luk at me!"
Spamming is almost always impossible to tell from regular building via script, so it has always been the job of admins to decide when to fire the ban cannon and clear the person's bricks. BuildBot is likely to lag your client while you use it, but not the server itself. The only time it might lag the server is if the server is godawful with an extremely low ping, and actually cannot handle recieving 30+ servercmd's each second.