I hope you weren't the one who investigated one of my old company's claims!
A female worker claimed against her employer for injuries sustained on a packing production line. As was the standard practice, my company (the insurer) estimated the cost of the claim at £2.5k. Having been told the woman would have to be off longer than expected, they upped it to £7.5k,whixh they would have paid without quibble.
When the solicitor sent in the claim, it was for £250k so they took a keen interest. She was claiming for life changing injuries requiring modification to her house and a specially adapted car. As it was soon discovered she couldn't drive before the accident, that bit went out of the window but there was still a fair bit left. So, suspecting potential fraud, they engaged a PI.
The PI came back after a while, very pleased, and showed the footage he'd recorded. The woman (who claimed she was housebound) was seen going out, then coming back later with a load of shopping, opening the front door and picking up the large dog that bounded out to greet her. As per usual practice, she was asked to visit a doctor to ensure she hadn't made a miraculous recovery. She hadn't and was still complaining of the same, life changing, injuries.
Then she was called in to view the footage and offer an explanation. That proved quite easy as the PI had filmed her next door neighbour.