So for this tournament you get 15000 chips in $400, but you can rebuy when you are at 15000 or below in chips and get 15000 more chips for just $200. Obviously we will take the rebuy at the beginning of the tournament to get up to 30000 in chips for $600, but should our strategy to be play extremely aggressively while re-buys are still open since if we get back down to 15000 in chips we get 15000 more chips for $200, while our first 15000 in chips to get in the tournament cost us $400?

I don't mean make making idiotic and crazy all in moves, but it seems as if we do want to open our ranges and gamble a lot more when re-buy period is still open?

The short answer is yeah... But I would be careful if I were you. People often just go mental in these games so I usually opt for a less mental approach n aim to pick up all their free money.

Once you buy in, I would treat that first $400 as a sunk cost. The difference between the original buy-in and the rebuy amount doesn't matter; what matters is the value of the chips at that price.

I don't think you should necessarily open up and gamble more. If someone is playing like a maniac, it would be a reasonable adjustment to tighten up and wait for him to hand you his stack, just like you might adjust to a loose-aggressive player in a cash game.

One adjustment for rebuy tournaments is that you can treat it more like a cash game if you are willing to rebuy. You shouldn't gamble more in the sense of accepting -EV spots in an attempt to get more chips, but you should be more willing to accept small edges and risk going broke because you are planning on getting more chips, just like a cash game.

Inducements to gamble go up but variance goes up even more. You need a considerably larger bank roll to be able to afford such a tournament than normal.

Also if it's a privately run event, I'd be suspicious of those running the event of skimming re-buy's and care should be taken in tracking buy-ins and total chips in play.