Nobody wants to be laughed at for crying manipulation but it happens all the time.

Cramer explains how he and others manipulated the market when he was a hedge fund manager:

http://mfgukclients.org/?p=1725

No sane investor would intentionally lose money by dumping into a thin market at the very end of day. Manipulation of small stocks is easier. The number of shares traded look large for MTO, but it is a small dollar amount because of the low share price. Continual bashing of small companies does have an effect to scare away potential investors and keep the share price down.