Sure there are the people claiming to have smoked acid and get effects, just as people have claimed to smoke shrooms and get effects...then there are those who have tried it and experienced nothing.
Upon combustion and reacting with oxygen, I doubt much of the LSD or related chemicals would remain. Here is the MSDS: http://msds.ehs.cornell.edu/msds/msd...11/m155123.htm (Look at Section 10)
That isn't what really matters here though, it is that acid is not cheap and in the United States is getting rare. Thus there is no logical reason for a dealer to take any amount of acid and put it on weed without telling the buyer, there would be much more profit in simply selling it for what it is by itself.