i've directly had laced weed several times.
a certain family member always had an abundant supply of weed in my younger years.
i used to do my own "lacing" however.
i'd mix it with speed or mdma powder. and keep it for myself.
or share with my friends.
tried to pack a cone with weed and cocaine, think i fucked it up somehow cos i didnt feel anything from the charlie at all?!
last time i touched the horrible green shit was early 2007
ripped the top bud off a plant. dried it out. coated it in a few points of some rather nice mdma powder.
me and a friend shared it. we wound up heading to maccas... by the time we got there, the hallucinations had begun. it was a very good stoned feeling.
but as a general rule, i don't know of anyone, nor have i heard of anyone who sells it laced. surely its not a smart business move.
and the one weed dealer i know that actually does lace his weed with shit, keeps that stuff seperate for himself only.
guess its kinda like crack, it is around, but you find that people are doing it for personal use, not for sale.