Probably no real difference, but if you think of it on an best case senerio level, if you're body can't really start recovering from your workout until it gets the building blocks it needs, then you may be delaying recovery by a half hour. That might sound bad but it's pretty irrelavent to a recreational athlete as total recovery time might be upwards of 48 hours (96 times as long as you waited to get recovery started)
One thing I've noticed about pre/peri workout nutrition is that once your body gets used to it, it NEEDS it. In other words, if you're always sipping gatorade during your workouts, you'll crash big time if you try working out without it. I've noticed the same thing with postworkout nutrition, if a client is religious about getting their post workout shake, they really tend to crash after their workout without it. Hence, from a purely practical standpoint, I recommend going without on occasion for an hour or so, just to keep your body adaptable.