Certainly there are additional complexity issues and those work to the benefit of law enforcement. However, there are some significant costs as well.
How confident really, is one that you aren't going to find 80 year old men willing to give their last few years of life for what they believe, money aside, or do we care whether their spouses are still alive?
The other real major cost is the social cost. If we do start making really fine-grained decisions regarding appearance, married status, etc. then we risk essentially ensuring that Americans are not equal before our government and that's something that is really hard to put a price on, particularly given the history of racial issues in the US.
How confident really, is one that you aren't going to find 80 year old men willing to give their last few years of life for what they believe, money aside, or do we care whether their spouses are still alive?
The other real major cost is the social cost. If we do start making really fine-grained decisions regarding appearance, married status, etc. then we risk essentially ensuring that Americans are not equal before our government and that's something that is really hard to put a price on, particularly given the history of racial issues in the US.