I agree it should be disclosed or registered as such. If you click on a "business user" you should find out what business they are involved in (manufacturer, dealer, and the name of the company). However, the people that post statements that they have a financial interest in, and don't disclose it, are likely to avoid registering as a business (or person linked to a business). Most people I feel are pretty honest and disclose these things in their post--catching the few that do not is desirable, but I'm not sure it's very practical.