At the department I worked with, one person would do it and the rest seemed to follow suit to "keep up with the Jones's". This was also after a major hurricane and tradisional uniforms were traided in for BRU pants and polo shirts. Interesting but comfortable combination.
I have a thigh holster that a friend gave me. His brother gave it to him and he couldn't figure out what to do with it either. Looks like the only time it would be necessary if you were using a repelling harness (SWAT) or something else that takes up the belt space. Otherwise, it looks like a good way to beat up your pistol on stuff.
Some of the Navy K-9 guys (master-at-arms) were I worked carry a pouch with a ball in it. This is to reward the dog when s/he finds something.
The pouch is located in the area a regular gun holster would be on the right /left side (which ever hand the handler would normally carry a gun).