Well, I suppose if there was something under the flap on a medium, or small frame speedloader. Doesn't matter whether is HKS, or Safariland, it would still have to be stuck with some sort of terrible force.
Two, the speedloader just catches on the rim of the cartridge, so, you would about never get it to even lock the cartridge in the loader, if something was lodged under the flap, on the back of the loader. N frame loaders are open in the back, in HKS.
The very first speedloaders I ever had were a set of old Hunt Manufacturing, rubber ones. They enclosed the whole rim, like a Bianchi speedstrip, but were round. I suppose you could jam something in there, and then hammer it hard enough to make it go boom.
This would have to be Murphy's Law at its finest. I learned long time ago never to say something is impossible. But I will say, "Not Bloody Likely"!!!!!!