Remember, no balloons are allowed at Animal Kingdom. Bright, distinctive, ribbon or cloth is your best bet. Whenever you leave a ride, look behind you-that's where they hide your stroller when you're not lookin! It'll make you crazy!
I purchased a large round luggage tag from Walmart and attached it with cable ties to the stroller handle. We have a stroller from Europe so not many people have them, but I didn't want it to be stolen either. I put our name, cell# and our home address and hotel name on it.