Hi there Anseo.
I've not noticed anything like you mention and I use Gravatar, however I totally understand that people are cautious about how their data is used and so on – and rightly so!
At present, that is the only way to have an avatar on the Practical Caravan forum, although this is something we're looking to change. You could always set up a Gravatar account, monitor where the avatar appears and if you aren't happy with that, delete the account?
I hope that helps.