I have read somewhere where a user sent a negative feedback or trust to a user just because he/she posted in another local board. There's nothing wrong posting in another right?. In my opinion, it is okay to post in another local board even though it is not your local board just as I have noticed some reputable forum member posted in our local board. I agree that newbies and other forum members should properly who they want to assign the role of being dt member.
I guess that it depends on what the rules are in each local board, but especially who you meet there. In the board I know best (Spanish) it is forbidden to post in English, and the abuse of google translate isn't a good idea neither. Anyway, I think we are quite flexible there and exceptions are permitted.
But it is true that I have posted a few times in foreign local boards myself (German, Russian...) to thank them for mentioning me in some other post or to add something to a certain topic I was interested in, and a few users raised this question -should he be banned?-. I'm afraid that still many people have the
black or white kind of mentality that can get you in trouble when you least expect it, either reporting you or giving you bad trust.
The abuse, of course, should be punished; for example, writing a thread and posting it in 10 boards using google translate in order to gain activity/merits or to fulfil the signature campaign quota. So, I think that the clue is the proportionality of the punishment, which seems that not everybody understand.