Its done all the time
I started a new job a few years ago, At the beginning of the month I had been unsuccessful at getting tickets for Glastonbury festival, I had mentioned this on facebook and a lot of people I was going to go with had gotten tickets so there was quite a large number of posts about it.
A week later I was then offered the Job and I accepted.
A few days after that I was contacted by one of my friends who said they had in fact been able to get me a ticket, there had been a mix up and they had only just noticed.
When I started the job I was asked if I wanted any holiday booked and I mentioned the 5 days off I would need to go to the festival the following July.
My new boss then asked “Oh, I thought you didn’t get a ticket”
I then replied something along the lines of “ Oh yeah I didn’t think I did, but then my friend… wait, how did you know about that?”
Cue embarrassed look from my boss and curious ones from the rest of the team, luckily for him I’m a nice person and said “Oh, yeah I mentioned it in my interview, sorry I forgot”. He thanked me afterwards and apologised for “spying on me”.
Luckily I reviewed my facebook history and removed any items that may have caused embarrassment beforehand, and it is something I warn everyone about, you never know when a 5 year old picture of you doing something you have completely forgotten about will stop you getting a job, and they won’t tell you it’s because you had a dodgy picture on facebook.