I agree with Kralik. If you have, say,
A Promise in play, does its strength bonus remain in effect if it is discarded? Of course not.
Better example: if
Gandalf, Leader of the Company is in play in Region 1, each other companion is strength +2. Surely you wouldn't suggest that that strength boost would remain in effect if he were killed, would you? Or further suggest that his strength boost would double if he were somehow replayed for a total of +4 for each other companion? That's just silly talk.
Radagast works the same way. While he's in play, the move limit is +1. While he's NOT in play, the move limit is unaffected by his text, even if it WAS initially affected at the beginning of that turn. If you've already tripled you surely don't have to move back a site or anything, but unless you somehow increase the move limit again, it's back to 2 from then on out. If you get
Radagast BACK in play, it goes to 3 again, but not 4.
It makes perfect sense to me. I can't understand why there's even a debate raging on this.