I do pretty much every day. My house key and alarm fob are on the "coin purse" and then I grab whatever car key I need for the day. And I've not had a problem with it at any security checkpoint. If I'm feeling extra paranoid, I put the coins in a pocket in a pocket in my laptop bag and then load it up in the bathroom after the TSA checkpoint.
One reason I prefer blunt over stabby/pokey. Less likely to require medical attention, less likely to come to the attention of the authorities, less likely to be seriously investigated IMO.
Ahhh. Gotcha. Yeah if a person took the coins out of the sap it would become a pretty harmless ugly leather key chain.