They sell those kinds of vests here, but they are usually made of lighter weight material with mesh in areas where actual fabric is not necessary - such as down the sides - for extra ventilation. I've seen a few people wearing them at WDW, but not too many. If it's not too hot and your vest is lightweight, I would say go for it. But I wouldn't wear a heavy vest, and I wouldn't wear one if it's as hot as it's been lately (some Orlando neighborhoods have had temps in the 100's in the past couple weeks).