Unless you permit rebuys anytime below starting, then short stacks are disincentivised from shoving. Nothing's perfect but it does reduce the Allin fest as the rebuy period ends.
After the rebuy, short stacks will still shove. Therefore, Paulo's comment is correct.
Might be my personal preference but I think the 50% mark or below rule plays well paired along with surrendering their current stack.
If you use the surrender the current stack rule, there is no need to set the 50% or below mark. There is often one player - that guy that always thinks he loses ever flip - that contemplates the surrender/rebuy. He then counts his chips and finds he is above starting stack. I will playfully joke with him that he is absolutely allowed to rebuy - it would be hugely -ev, but there is no reason to say no, as there is no inherent advantage once you surrender the chips.
Except that person has paid double and his equity has only improved by one buyin, whereas all the other players have only had their equity reduced by one buyin. Also increasing the stack size over starting stack by a rebuy has a less effect on the game overall versus shoving and dumping chips, which you are trying to prevent.
One buyin in a tournament is a small price to pay for a 200% chipstack advantage. Even if the opponent eventually rebuys himself, they won't have the same advantage that you had by rebuying to a maximum chiplead (unless he happens to also go down exactly 1 BB in the first level).
Which has a worse effect on the game, dumping one BB at the start of a game or dumping your remaining stack at any point? Which is more likely to happen, someone dumping a small amount of chips at the very beginning to increase their equity a small amount or someone dumping a larger amount of chips at the end of rebuys in order to increase their equity from almost zero?
Both are extremely likely to happen without the surrender rule. I cannot imagine
not doing the single BB fold/rebuy. I've played in casinos that allowed a rebuy if you are at starting stack or less, and nearly every single player took it. A rebuy is inherently worth more early than it is late.
Neither will happen with the surrender rule.
It is not -ev to dump your chips and rebuy when you lose a small stack to someone else but gain on everyone else in the tournament by rebuying. If you have to surrender your chips to rebuy then you might as well shove before that because there is always the chance you win and then don't need to rebuy. Shoving is obv more +ev then simply surrendering.
I hear what you are saying. It has been discussed before, and some very good players agree with you. I will not disagree that surrendering is always -ev, but giving those chips to an opponent is even greater -ev.
I can say this: since I adopted the surrender rule (which I took from the WSOP, and has spread to the Horseshoe Tunica, Aria, the Venetian - and probably everywhere that good games are run) we no longer see blind shove fests at the end of the rebuy period. You can get aggressive with a short stack, or you can tighten up in hopes of catching a monster, knowing that you always have that reload. The point it, the individual player has options. Options are what makes poker great.
