Welcome to planDisney, Andrew!
I’m so excited to hear that you’ll be visiting Star Wars Galaxy’s Edge with your family so soon! WOOHOO! Be sure to stop by the
Milk Stand while you’re visiting to get a cold, refreshing glass of Blue or Green Milk! (While I know the Blue Milk is a fan-favorite, my family actually prefers the taste of the Green Milk — consider giving it a taste!)
I have seen small signs brought into the theme parks by Guests to use for baby announcements, engagements, happy birthdays, etc. with no problems, Andrew. I checked the official
Property Rules, Policies & Regulations page, and this is all that is said about signage that is prohibited, “Unauthorized events, speeches, or use of any flag, banner, sign or other material for commercial purposes, or as part of a demonstration.” While Cast Members and security members will have the final say, I don’t think that you’ll have any problem with your son bringing a small sign to ask his girlfriend to a school dance! I would recommend making sure it fits into one of your park bags so it is not a nuisance on attractions. (I cannot imagine that this would be the case, but also be sure that the content on the poster is family-friendly and appropriate to be viewed by other Guests of all ages.)
I hope your son and his girlfriend have a magical visit AND that they enjoy their dance later this year! How magical! If you have any additional questions, we hope to hear from you again at planDisney!
May the Force be with you,
Allyn