I worked a worker’s compensation claim once, where a contractor claimed that due to a back injury he had basically become immobilized, sure enough he had Facebook posts that included zip lining - and was able to subpoena the waiver he signed declaring he had no injuries - and other posts like “drinking getting fucked up and dancing all night at the club” with pictures. So yeah basically people are doing the job for the insurance companies and lawyers that they used to have to hire and pay PIs to do.
It's not more invasive, but it's much cheaper. Allstate used to have to pay a rent-a-cop to park outside someone's house for every dubious claim. Now they can surveil millions of people almost for free. That's a huge difference.
Also, I assume you can't PI every case. So social media may help as a pre-selection step for PI-work.
They are expensive to pay out and often real chronic back pain is not easily differentiated from fake chronic back pain by a physical. The diagnosis is made based on patient reported pain.
The easiest way to confirm the diagnosis is observe if the claimant is behaving in a manner consistent with debilitating back pain.
I'm not seeing how this is more invasive. I mean, people are making certain content public. Having a PI parked up the block in a car with tinted windows seems much more invasive and that is business as usual and legal for the insurance industry.