Basically, the way I see it is that sponsors are paying money to have you as a person and a player representing them.
If you want to spout ****, feel free. If your sponsors decide "we can't risk being associated with that player" then they'll feel free as well.
Basically, it doesn't matter whether or not you put a disclaimer on your posts. Whatever you put in print is your opinion. As your team lets you play with them, that reflects (at least a part of) your team opinion. As your sponsors are paying money towards your team, REGARDLESS OF ANY DISCLAIMER, that opinion reflects onto them.
As a sponsored player, you have a responsibility to "censor" your opinions, especially when they are printed in the public domain.
Also, there was a quite interesting speech provided by one of the captains at the recent D7s when thanking sponsors. Personally, if I was sponsor of that team, I would be asking for my money back immediately. It might have been a throw-away comment, but especially as captain to an audience, those words should not have been spoken.