I think it happens quite a bit, and tbh companies often don't mind even if you hint or tell them that's what you will do. That's because the most difficult bit IME is organising the childcare and missing your child for the first 6 weeks or so. After that work doesn't seem so bad and I'm sure a fair few women who had planned to go back only for the minimum period actually end up staying.
I dropped a day at the end of 3 months after I'd gone back, so I didn't have to pay anything back but I still ended up working shorter hours. DS was very happy at nursery by the end of two months back at work, I would have had to give a months notice to leave, so that's pretty much when I made my decision to stay.
Am mostly going back in case there's an opportunity to take another part time job in the same company... also to see what the economic climate will be like then - would like a steady job if it's all gone properly tits up.
Realise I am being a bit rubbish to call it taking the piss and then asking for experiences - sorry!
I was going to do that but in the end changed my mind and we were ready to pay back the money but my employer ended up waiving the maternity pay I owed which was really kind. I know my sister went back as a teacher for just the required time and it worked ok but was really tough on her organising childcare and missing her little one etc.
I'm doing it. Told them I was leaving as soon as I came back. Am doing a mad mish mash of child care though - would've been better to go part time for 6 months in hindsight but I just want to get the HELL out of there It's not taking the piss at all it's fulfilling your contractual obligations . .
Well I am doing it - over Dec/Jan/Feb - with a mishmash of childcare like ephrin lucky DD is a happy social girl (so far anyway) so hopefully will enjoy it. Part of my reason I realise is to show DH how mad it would be if I did go back to work full time and how much extra childcare he would have to do...