The Sil I just scored today at WalMart also has a little fraying on the selvedge. But just inside of that you can clearly see that the fabric looks different due to the silicon impregnation. The impregnation did not completely reach the edge of the selvedge. On the cut edge of the fabric it definitely does not fray. What I found is also very noticibly ripstop. It's hard to tell in your picture if yours is ripstop.