I think this calls for some ecological analysis.
- Who is selling the locking gas caps? Who is buying up all the locking gas caps - honest motorists or the siphoning gangs?
- Who is buying the siphons? Who is selling the siphons? What is the effect on other activities that use siphons?
- What is the relationship between the supply/demand of locking gas caps and the supply/demand of siphons?