And how will you know?
Some voc counselors hired by workers compensation insurance companies are just plain dishonest (and there are qualified, ethical counselors as well) who will do anything for their client - and their client is always the insurance company, never you.
Sometimes its not enough that their report casts everything you do in a negative light - while leaving out all of the times the voc counselor cancelled meetings at the last minute, showed up late, or didn't have any job leads available. But some will just straight out make stuff up - saying you told them you wouldn't apply for a job when you just asked a question about job requirements, even little things like saying you agreed to meet at a certain time or place. They want to show a pattern of someone who is not trying to find suitable light duty work after an injury so the insurance company can stop your benefits.
How do you know and what can you do about it?
Get as much of it in writing as you can. Use email whenever possible to confirm what was said. Get copies of all of the reports and emails or other documentation the counselor sends to the adjuster (you are entitled to this). Keep your own records of everything - job applications, job descriptions, job leads, etc. - make a copy of everything.
Remember, their goal isn't really to get you back to work - it's to get you off of workers comp. That's a big difference and they accomplish that goal if they can show you weren't cooperating with them - at least to stop or suspend your benefits.
Unfortunately, a lot of the time you don't find out until its too late. Take these steps from the get go to protect yourself.