Sand blasting is pretty common around my areas when there is little cannabis to be found and dealers cant get hold of much.

Especially last year when a load of growers were busted during the summer.

http://www.thepoorhouse.org.uk/beware_glass_grass

This is probably the main reason I would grow my own, I havent used a dealer since I was 19.

I know what strains I like and which ones I dont.