Well, they frequently say that the trend is your friend, but I believe that the same rule does not apply if you are a whale or a market manipulator. If you are a whale/manipulator, then you want to maintain some control over the rises and falls, and of course from time to time, even the manipulator will have to let the trend go when the momentum is working too strongly against his/her/its ability to control it. Ultimately, keeping the situation in control is going to be much more profitable for someone with a lot of capital and moving the market...... and if the price goes up too much, then it takes more capital to control it... and then there would be a problem with new entrants and other whales trying to get a piece of the pie.
and this would be where being 'friends' with the exchanges would prove quite prudent!
Ya think hookey shit aint going on, on every single exchange, Stamp included?
I believe that it is possible, but really it seems too much too assume that to be the case. There are ways to play the system without necessarily assuming that there are so many bad players. For example, there are a lot of scenarios, even where a real wealthy whale may consider in his/her/its interest to manipulate the BTC market downward, even though he is losing money because he makes money in other areas by keeping BTC down. In this regard, you need not assume that every single exchange has some bad actors or foul play going on at a grand level.
Surely, most exchanges likely have some profiteering going on at smaller scales, but that kind of inside profiteering does not necessarily conclude that they are in bed with some of their highest rollering customers.