It sounds more likely that your employer has changed their settings!:(
Programmes like Websense have a huge database of websites and try to fit each site into one of about 100 categories. They do this by scanning each site for keywords and carrying out analysis from the results. They don't rely on webmasters providing them with the info as it would be too easy to cheat!
It looks like your company either has got an updated database from Websense which now includes NMS or they have altered the list of categories you are allowed to view to exclude vehicles!:(:(
My employer bans access to any forums (or fora for the classically pernickity) but simply looks for the word forum in the URL. NMS escapes because snitzforums isn't recognised!:)