Electrophilic aromatic substitution with fluorine Why don't we usually use diatomic fluorine in electrophilic aromatic substitution? 

Is it because fluorine is a potent oxidizer and will react with the carbons? 

What might happen if we reacted benzene with diatomic fluorine in the presence of some Lewis acid such as boron trifluoride? Would we get the expected product: monosubstituted benzene?
Fluorine reacts so rapidly with benzene that aromatic fluorination requires special conditions
and special types of apparatus. Even then, it is difficult to limit the reaction to monofluorination