I doubt there would be any negative effects to your cigars. That being said, I'd probably bitch-slap any friend that suggested it (well, not really). Cig tobacco is dried well beyond anything that's salvagable. You won't be helping the cig tobacco out in any significant way. Tell your friend if he's worried about them going stale to throw them in the freezer. I actually do know people who do this and they say it works (no idea why or how).
Like I said: probably no harm can come from it, but I see no good reason to do it. If he wants to try it, send him to ebay to pick up a cheapo $10 humidor to try it on his own.
