Here is something to think about.
Not long ago, I shared a pic of mine on someone's personal Facebook page. That personal used it as their personal profile pic and my watermark got cropped out. At that point, I did not have much an issue with it, even though it really screwed up the pic.
A week ago, a company took the same cropped image and used it on their company page promoting the company and product. I contacted the company requesting that they use the full version of the image. Even though the damage had already been done, I tried to be nice about it due to the fact that the company has a working relationship with people that I work with on a semi-regular basis. Even though I was still talking to the company about my request, they drug their feet about honoring my request. I ended up just having the image removed from their page. Lesson learned and possible future working relationship ruined.
Here's the deal, each photographer is different in regards to protecting their work. Some care, some don't care. Some are fanatical, some are somewhat fanatical and some would rather work things out in a nice way. It all comes down to the photographer and how they feel their work. Listen to everyone's advice and use what you can and store the good points for future use, if need be.