Like in the Netherlands, there could be specific venues for cannabis use (sans tobacco). Smoking wiet and hasj on the street in the Netherlands is actually illegal. No matter what the substance is, there are always both considerate and inconsiderate users. I am always careful not to blow tobacco smoke around children.
Smoking tobacco indoors (aside from in your own home) is already illegal, and smoking cannabis and driving should not be allowed.
A contact high outdoors is impossible unless you're absolutely surrounded by people smoking pot.
Skyhook: the 'bamboo bong' you saw is a traditional Chinese tobacco pipe. I believe the term 'bong' comes from the Vietnamese name for the almost identical tobacco waterpipes used there. In Australia, however, I think pretty much all the (billy) bongs you're likely to see would be used for pot.