I voted yes. When I read something I want to know if there are relationships which might have influenced what was said. I have no problem with honest expressions as long as I know there is the possibility they have been influenced. In most science papers it is now required to disclose all associations, even if fairly slight or in past.
The difficulty is that there are a myriad of potential relationships beyond employee ones. Like I suspect most NamePros members have some sort of affiliate relationships - should those be included? What about people that have blogs or lists that are funded by a variety of companies? Would get messy.
I think it is good practice, if there is any chance of perceived influence, that the person indicate in their post any relationships. Alternatively, simply not post when they feel compromised on a fair view on an issue.
A couple of times over the years I have read a negative opinion on a service, only later to learn that the individual was involved with a competing product, not that being indicated in any way. I don't like that.
Bob