= new reply since forum marked as read
Cats gotta cat. 
Our latest cat showed up at the house next to mine, neighbor called to see if it was ours.
She does like to feed cats, but only on her deck, never lets them in the house.
Few days later the neighbor across from us called, same cat, was it ours, etc.
They actually decided to keep it, but..same rules...no indoor cat, only fed it dry cat fud, and their gang of young ones thought of it as a furry doll, to be carried around until they got distracted with something else and dropped it.
well, the cat put up with this for a few weeks, then I spotted him in my yard, gossiping with my old cat.
Few days later, I noticed the new cat was not leaving my yard much.
then one day...
he walked into the house behind me when I was carrying in the groceries, walked over to the hutch where we keep the dry cat food, right past my dog, who did not even blink !!!!
sat down and waited to be fed.
And that is how we acquired our 2nd cat.
He was at least a year old, skinny but not starving, extremely well mannered ( have to be, to put up with 4 kids dragging him around) and a gorgeous smoky blue/grey.
He gets to be indoors when he wants.
He gets canned and dry food.
He gets vet visits. vet declared him healthy, neutered, obviously someone's pet at one time.
Our neighborhood gossip line never produced a previous owner,
the family with kids was grateful he moved on, because the parents "really don't want to deal with pets",
and the animal control/sheltter never got a missing cat report on him.
I think he test drove a few houses till he found the one he preferred.
And..he is the 6th or 7th cat who chose to live with me of his own free will over the years.
so, yes, it happens, and in absence of other evidence I too would feel comfortable in assuming that your cat has decided to grace someone else with her presence.
And may be back, you never know.
I know you'll miss her. 
