Of course, if the site gives a certain amount of timebank to all players, and also some seconds to make decisions, they can use it in any way they want, including as a personal strategy. But I honestly don't see how this can be positive to the player.
In a poker tournament, or even in a cash game, the goal usually is to play as many hands as possible, right? In some situations you might want to slow down and tank a bit more, and that's ok, but let's say that the tournament has just started, what would be the profit to do this? Why to play less hands? Increase variance? I can only conclude that it is to tilt players.
When we face someone who does all this tanking, we have to do our best to not tilt or get annoyed. We can't do anything about it, so why bother? But I think this is not ethical at all. I remember that Martin Kabrel in the
wsop, the guy is so annoying, but what can one do?