While investigating your claim for LTD benefits, the insurance company may spy on you to help determine whether you really are disabled. It is insulting, intrusive, but most likely not illegal.
The insurance companies will hire a private investigator, at a cost of several thousand dollars, to follow you around and record you, or at least take photos. They will search for any social media accounts you may have. They may order tax returns and other items.
In order to combat this spying, there are two important things to keep in mind:
They don't believe you. They don't want to pay anyone money, especially one where they really don't believe the disabled worker.
If you suffer from a disabling condition that is hard to prove with diagnostic imaging, such as fibromyalgia or Complex Regional Pain Syndrome, then they are more likely to conduct surveillance.
Sub rosa means "under the rose" or secretive. Well that's exactly what the insurance company is, secretive, when they hire an investigator to go follow you around and watch you and/or record you on video.
This surveillance can happen at any time. It may have happened already. Anytime you leave your house and go outside, you are at risk of being surveilled by a private investigator.
As long as you are out in public and have no expectation of privacy, this practice is most likely not illegal (laws vary state by state).
Insurance companies will scan the social networks to look for your profile. They want to see photos, discussion, evidence of you engaging in activities you said you cannot do. Maybe you say your back pain is so severe, you can't jog like you used to.
But they have video of you running a 5 kilometer race just the week before.
So you have to be careful what you post on any of your social media accounts. Any contradiction, even if it is just an appearance of a contradiction, will hurt your case.
So what do you do?
Do not exaggerate your disability. If you can run for 15 minutes a day without pain, say so. Don't try and claim you can't run at all when there is video of you running around. Don't claim you cannot lift anything heavier than 5 lbs and yet, you posted on Facebook, a photo of you lifting your friend in the air.
Again, the most important thing is to fill out your application for long term disability benefits as accurately as possible. If you can't jog, then there will be no video of you jogging.