I'll bet on your 5% unsurity then. I had them al over my tank, when I bought 1 plant from P@H. was a real problem until Mr Betta discovered their taste. The were most definately clear blb of jelly with white dots.
I also have ramshorns and trumpets now, thanks to an ebay plant put as yet have not seen their eggs.
Since Mr Betta found them in addition to me removing the hatched snails. there doesn't seem to be a problem anymore, and the trumpet snails are quite cool.
Not so keen on the ramshorns because when they are presses up against the glass at the top and the light shines through them they look like a huge mite or something until you get them out.