I've found that to be the same for me. Any mult-bagger play I've made, has almost inevitably been restricted by the so-called major brokerages (Etrade, TD, Scott).
And of course they ALL tell you its done to protect their investors....cough cough...BS....lol
From what I can tell, its done because those brokerages have sections that are in bed with the hedge funds responsible for endlessly shorting many of these OTC/OTCBB stocks. And most times they simply short them into oblivion, either because they are scams (which most are) and can't muster up enough interest to generate the Buying pressure needed to force them into covering.
Sure, sometimes they have to cover and thats when you see the massive 10,000% runs. But most times they cover when the stock reaches .0000/.0001 if at all.