Well, keep in mind, this idea is for the players more than the owners. Most of the people who have them are probably people who would, under the current system, have a no-trade clause. So before you say that the owner gets screwed over in situations like that, take into account that usually, under the current system, they would never get the chance to trade in the first place. so the net effect is still being less screwed than now.
I'm not sure how I feel about the problem you present. Definitely not one day. If you're going by rollover determining days, then Id actually say 3 days minimum. If you're going by actual 24 hour period (I'm not sure if there's even a way to do that in GLB, though) then maybe 2. But I don't think you should be able to go away fro a weekend with one of these clauses and come back to find yourself traded. If you wouldn't mind that, you'd sign an open contract rather than one with either clause. I want to move away from the idea of it being like the owner grants the player a few hours or a day to reject the clause and make it that final say is with the player, on his timetable. And if that doesn't work out for the owner(s) then oh well, no trade occurs. Which is no net change from if there had been a no-trade clause.
That said, if a player has gone long enough, I'm not against the owner getting power back, but I'd actually rather say something like... say, if the player is inactive, he has 2 rollovers to come back and veto (or accept) the trade before it goes through. And as long as the player is active, the trade doesn't go through unless he accepts it. Or, if it does, then there's like a day 5 window before it does, or something.
Essentially, it's the conceptual difference between the player having a clause in his contract that he can veto trades and having a clause in his contract that for a trade to go through, he has to accept them. While both have merit, I'm proposing the latter. The player isn't getting the ability to pop in and veto if he has time, but rather, no trade happens unless he actively approves it.
The only issue being the trade deadline, which you brought up. For that... I tend towards saying if the trade deadline hits, the trade doesn't happen. However, I also see the merit in saying that, like, if the player is inactive 3 days when the deadline hits then the trade goes through.
So... that's where I stand on this.