Situation:
You're in a fairly easy level with a boss at the end of your run, so you're trying to save energy for the inevitability that you will need to revive yourself when your party dies.
But you die. And someone else dies. Bad luck, but no reason to panic, plenty of help still around to health-split you back to life. Unfortunately, the other person who has died is either new or just came into a windfall of energy because he decides, with all the kindness in his heart, to revive you with energy.
So now your revive cost has doubled without your consent.
Solution:
Allow a player to decline when being revived by others. This gives the player more control over his play experience and allows him to save every bit of energy he chooses until the end of the run, when he really needs it.
I'd have to second this suggestion, I don't know why I haven't thought about it before. [Sad to say, I've done this before :(]