There is a lot of truth to that.
A good way to check it out is to look a the volume traded. Sometimes if it is a thinly traded stock an hour or two may click by before another trade is executed, unlike MSFT or Exxon where trades occur every second
Sometimes, insiders and other rogue traders will run the price of the stock up and draw in a few new investors and then dump them at your expense
Not all pink sheet stocks are like that but it happens quite often
