The Mac bag isn't padded, but there is room enough to wrap a quilt or something around your stroller and still fit some other stuff in it. That's what I did for one trip where I was traveling alone with DS at 9 months - I just checked the stroller with luggage. No problems at all.
You mentioned that you're gate checking - just a thought: if you put it in a bag you run a slight risk of them getting confused at your destination and sending it to the baggage claim...that just happened to us in May with a Quinny Zapp stroller, granted the Zapp folds really compactly and when in the bag it looks more like a sports equipment bag than a stroller bag, but it definitely had the big neon gate check tag on it. It was pretty discouraging to wait around at the gate to have them tell us to go try baggage claim. At least it was there, but kind of defeats the purpose of gate checking IMHO.
We have gate checked non-bagged strollers several times without a problem, but I have heard others with not such good luck. So I guess it just comes down to there being a slight risk with whatever stroller transport method you choose.
Good Luck!
