Yes they move them for safty reasons and also to deter people from stealing items from the strollers. Remember they are use to having to bolt and glue everything down, for the safty of there guest and the preservation of there displays. They are just trying to do the same for youe personal items.
Universal is a very good place and guest oriented. But when it comes to stollers it does get a little irritating. It is at any ride, store or restroom they must move them for safety and to make sure the path is clear. I had this happen too myself on shrek, the stoller was in stroller parking but due to mardi gras fencing, staff relocated the strollers and many parents were upset because we werw not notified.
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