I don't know about the buckle itself but I would say try feeding the ribbon back up into the buckle creating more friction points on the ribbon. Or a half hitch in th ribbon will stop it.
I think to mod the buckle you would have to put some ridges on it and it would tear up the gg ribbon.
just me thinking.
Yosemite Sam: Are you trying to make me look a fool?
Bugs: You don't need me to make you look like a fool.
Yosemite Sam: Yer deerrrnnn right I don't!