I have slime tubes on my balloon tires, and got a pin-prick flat from a piece of glass. The tire refilled great at home, but then kept re-flattening when riding.
Bike tech said that the regular thickness tubes (which are darn thin) aren't stiff enough to hold a slime plug, so they move around and leak, but that the slime is effective in slowing the leak and making it possible to get home (in one case, I had to keep stopping and pumping to make it home, but did make it home).
He recommended using thicker heavy duty tubes if one wants to use a slime-type products. I just bought slime's "super-thick" tube to have on hand next time I need a tube. Fingers crossed till then!