I have a stray female who has become my cat's girlfriend. While I have
a magnetic cat flap, after finding my cat letting her in by poking his
nose out to release the flap, she has found out that by pulling the
flap outwards with her claws she can get inside. I'd like her as mine
as she keeps Scratch (my cat) good company, but while she won't run
away from me, she always keeps her distance and runs out when I come
downstairs in the morning. She has been "done" by the cat protection
league after 3 litters, which has stopped the rest of the local
tomcats hanging around.
The point of all this? I spent more money replacing an ordinary flap
with a collar based one only to find love (even among cats) can
overcome any obstacle. I don't mind her as long as no other cat
figures out how to get in!

Juan & Scratch