i'm not sure what these ppl are talking about, but most schools let you defer. many of my friends were accepted to med school and then deferred for a year for reasons of wanting to study abroad, travel, etc. it's not THAT hard to get a deferral approved. if you do want to simply travel, you probably shouldn't approach the school with that reason, though haha. you need to come up with a good reason, like wanting to take further studies before you embark on your 7+ year medical education journey. once you get the deferral approved, you can do whatever you want.
i personally wouldn't want to defer ever simply due to the fact that you have so many years of medical education in front of you. I want to finish, not delay any longer!