I doubt they are burning smart. Maybe need to learn to stack up a camp fire the right way. One's dealings stop at their property line but when it does not there are two options. Approach and try to help them understand and failing that check local codes (I suggest doing that yourself).
Here burn barrels are outlawed, but one can use "pits" low walled dishes of sorts that allow air for proper burning and also have a screen to catch embers.
We had a nice fire a couple weekends ago. And plan for one this weekend as well.