Might make the players feel better/inspire them, so not that fussed for that reason, but I would be more concerned why they felt like they needed to do that though, if that's the case.
Might just be a nice thing to do, and brings some goodwill, so as long as it's not within an hour of the game starting, and not getting in the way of anything warm-up or team-related then it's probably not a bad thing.
I would rather they were there pre-game and early, rather than being there at the end of a game which has just been won/ lost and was crucial etc, that's a time for the team to celebrate or to not try and make light of a loss.