i googled this page in literally 2 seconds:
http://www.fairfaxcounty.gov/living/animals/wildlife/archery/urban-archery-in-fairfaxcounty.htm
and if you check out the associated rules, it appears this is a very safe operation.
I hope the average 7 year old is not riding around unsupervised. The parents ought to be able to tell where the hunting is going on. Apparently the hunters cannot be anywhere near trails and there will be signs and survey tape up.