We took our Triumph MacClaren for our 18M old this past Sept. We always parked it where there were lots of other strollers. Never had a problem. We did not leave anything in it. I carried a tote bag with our stuff in it.
We enjoyed having our son in the stroller, but found it troublesome to lug the thing on & off the buses and carry it upstairs to our second floor room. It's an umbrella stroller, but it was still seemed a little heavy, probably because we were exhausted.
Also we were surprised that we couldn't take the stroller in Imagination or Living Seas at Epcot. So we ended up carrying our son quite a bit there. He can walk, but we'd never get anywhere. He tends to check all the trash cans, outlet covers, etc.
We stayed at CBR, but I sure was wishing we were at the Contemporary so we could just wheel the stroller, kid and all, onto the monorail.
Have fun!