In case anyone was curious, mailing cash is legal according to this Snopes Article - www.snopes.com/legal/postal/sendcash.asp
Can't find a current USPS FAQ, though.
Can't find a current USPS FAQ, though.
A transient mailing of discrete paper cash is different than a call-to-action requesting coins that will be delivered to the same address on a regular basis.
As someone who lives in the Bay Area and has seen car windows smashed for the change in the cupholder and a friend's motorcycle knocked over to get the flattened soda can that was being used as a stabilizer, yes, that's a security concern.
Before reading the Snopes page just now, I would probably have said that I was pretty sure mailing cash was technically illegal. But thinking about it now, I have no idea where I got that idea from.