If I'm home they uasually don't have collars on, but even i'll admitt that this is a very bad pratice for me as they can easilly slip out the door when you least expect it... I have children who run in and out to friends houses and its so easy for them to slip by us undetected sometimes... they are just so darned fast!
As far as people not wanting to return them... I have their tags made by a guy at the street fair who makes them while you wait and can do the engraving on BOTH sides of the tag... on one side I have him put "LARGE REWARD" and on the other "PIXIE (760) 555-5555" And thats it.... I had him make 9 of them!!!! He thought I was so nuts at first but then I explained that I have collars and harnesses for different days and colors and whatnot... so I wanted there to ALWAYS be a tag on the girls! So this would ensure that there would be!
I am having them redone though.... I will now include their microchip #! someone will be lesslikely to keep a dog that they KNOW is microchipped... And the words "LARGE or HUGE REWARD" really gets $$$$$ floating around in peoples heads! They start dreaming about how big the reward might be!!! And that alone makes calling to turn in the dog very tempting!
I'm often asked by people who are printing this on tags of their own... What is a huge reward? Some people can't afford what some would think as HUGE... but thats just it... while the finder may be thinking thousands, or hundreds... its up to you... as long as those words bring your baby home its up to you what the reward is, and you never disclose that over the phone.
I'm all for collars... Big dogs hang themselves too... thats what I remember my vet telling me when I asked about Pixie wearing a harness or collar, he said that, that the numbers of pets that go unfound each year by not wearing collars are far greater than the number that are injured from wearing them. And I still, out of fear and reading posts did not make her wear one when she was younger... but I have her wear one alot more now...