I have a theory
I think that "correct" strategy (ev- maximizing) in rebuys is in principle no different from correct strategy in a regular tourney. The problem is that your opponents will not play correctly (as in regular tourneys), not by far. Thus you have to adjust accordingly. This pretty much means that you must play a little looser. Your opponents (the better ones) know of this and take your moves a bit more lightly. You know that they know. Etcetera. The ball is rolling.
It's like a gigantic Nash equilibrium being badly broken, even if no bad players are in from the start. It becomes clearly correct to deviate considerably from some (perhaps nonexistent) unbeatable/unexploitable tournament strategy because we can exploit better playing differently.
A priori, there was no reason to play differently, not for anyone. But that delicate balance becomes broken if people were to deviate. It doesn't take anyone to actually deviate before people adjust to the deviation.
Some sort of mass leveling war make rebuys substantially different from regular tourneys.
Put it differently: If you knew for sure that the players at your table would not play differenly from a regular tourney, then, as far as I can see, there would not be a single reason in the world for you to play any situation differently from a regular tourney. [Why donate chips? You can't repair a big stack all that easily by just rebuying and getting a starting stack because your opponents will not donate back. People won't gamble.]
In reality, the opposite is true. You know almost for sure, that your opponents will play differently from an ordinary tourney, even before the first hand is played. You must adjust accordingly. [People will gamble. You can rebuy and expect to play a big pot soon again with decent chances without having the absolute nuts.]
What the proper adjustments are, I'd like to know. It still takes an idiot in my book to call a big reshove preflop with 66 - even if you can rebuy. Perhaps there are no generally applicable advice at all - except that people are looser with close to 100% certainty.
Wether to make light calls, gigantic all-ins with monsters, or slowplaing mosters, or value betting thinner, or whatever is perhaps entirely opponent dependent. It's up to me to read the table. In that respect poker does not change one bit. Thanks goodness for that.
/Johan =