To be fair, in regards to the health issues and whether it gives you cancer or not, isn't is exceedingly common for cannabis to be mixed with tobacco, to get more joints out of a single amount of cannabis?
If you're smoking tobacco with cannabis then you're at the same risks for developing mouth/throat/lung cancer and your second-hand smoke can cause the same damages in other people.
I might be mistaken, but in the Netherlands, isn't it legal for people to smoke cannabis in public as long as it's not mixed with tobacco for this very reason?