Hi , Spit !
I have found that they rarely work . When we go to train shows with the Museum traveling show stuff we have had to resort to yellow posts and chains around the tables too . Does it work ? NO !
The TEX- LUG ( LEGO USERS GROUP ) I belong to goes to train shows too .Yellow posts , Good spacing and signs all over the place ( Please ! Do Not Touch - It scares the minifigs .)
These do get a chuckle , But they don't work either . I have come to conclude that my generation was the last to really endorse the rule , Don't touch , it isn't yours !
Now at the Museum ,even with 18" plastic guards on the edges of the display layouts , the kids still try to reach over and touch . The parents don't say a word of admonishment even if the child de-rails a running train !
So you see , it's a burden we are stuck with ! When I was a tad , many centuries ago ( to hear my friends tell it ) I was told quite sternly," you touch Anything where we are going , and I will paddle you with you pants down , right there! " . Now , that is considered child abuse !
I guess admonishing your child causes mental trauma or something . Oh , and yes, Adults are just as bad at times !