Look at most law enforcement/security/corrections uniforms and you will see they all have clip on ties. The reason is that if you get into a fight, the bad guy won't grip your tie and use your head as a yo-yo. The lack of grooming standards has always been a gripe with the FAM's. We were required to be clean shaven and wear professional clothing even though we were "under cover". If anyone should have a professional appearance, it is the TSO's who are very visible.