This is the true value of the Parma Magica. Parma magica blocks that "creepy fellow that deserves to be toched" feeling of The Gift, so you can interwct with your fellow mages as if they were normal people. People not protected by parma Magica are still affected, though, so will misstrust your magus regardless.
Simple Answer: The negative social effect of the Gift is magical and thus blocked by the Parma Magica. This is, however, a bit of an oversimplification as it has been established that possession of a Might Score (which also confers Magic Resistance) does not necessarily confer the same immunity to the suspicion and loathing inspired by the Gift.
Incidentally, it is also mentioned (in the core book?) that those exposed to the Gift for extended periods of time, such as red caps, can eventually come to recognize their hatred for magi as being magically inspired and thus ignore the worst of its influence.
Its been answered quite succinctly, but to confirm:
If the person a magus is not talking to isn't protected by the Parma Magica they will experience the negative effect of the Gift. Note that some supernatural entities ignore the Gift effect. Don't bet on it, though - chances are the dragon you're about to go negotiate with will get a 'must burn' vibe off your Gifted magus. That is why companions are so useful. This is also why Gentle Gift is a major virtue.
So yes, your maid, cook, covenfolk, companions, shield grog, apprentice, spouse, etc. are all affected by your Gift. If you extend your parma over the person you're talking to that can help. That said, most people's reaction to the creepy man saying 'let me cast this magic ritual on you so you'll like me' isn't going to be exactly positive.
The big point though: if your magus is present and keeping a low profile their Gift effect doesn't come into play. Even a blatant-gift'd person can get room and board at an inn if they let someone else do the talking, keep to themselves and don't try to get involved.
So, ruleswise: A mage, not to burden someone with his/her Gift's negative connotations, would have to raise the Parma Magic (about 2 minutes); would have it's efx on till next sunrise or sunset, whichever comes 1st... & would have to recast it again to mitigate, again, the Gift's negative emanations; & so on & so forth... Right?
Your saga may vary, but in my sagas, every magus does his parma at dawn and dusk. Even if he was sleeping, he will go back to his bed. But he does his parma ritual, anyway.
The real ritual is not described. IMO it's a mental ritual with a physical component, but related to the sigil. It's so minor (it only takes 2 minutes to do it...) and normally it's done in private (in your room, when you are alone, when you go to the latrines...). I consider that if you want, you can almost do it without being noticed (it's a stealth roll vs awareness).
And, due to that fact, we are not bothered in any of my saga by the other players gift... but our companions, grogs and the NPC mundanes are, of course.
Most magi cast it every sunrise and sunset without giving any thought to this. If you were to ask them, maybe they are proud to be of the Order, maybe for defensive purpose, but not for trusting other Gifted individuals.
The only saga I've ever been in which didn't do this was - I think - a 3rd edition saga... whichever edition it was were Parma blocked the "magic" of everyday life, like tasting good food or enjoying the flowers. We had a few romantic players whose magi were willing to forgo magical protection in exchange for enjoying their lives. Otherwise, yeah, we've always just had a blanket assumption that magi renew their parma at dawn and dusk unless there was a plot point in a story that prevented it (such as being at table during a noble feast at dusk).
I like to include the option for the other as well.
Where the magi can reduce the social penalty by turning part of the Parma inside out.
I´ve usually run with the rule of 2 pts of PM is enough to reduce penalty by 1, while acting as a casting penalty of -10(and of course not adding to magic resistance while so used). (or 3/-15 if you want it rally hard to use)
Essentially it allows a magi with a high score in PM to interact more easily or even normally with those unprotected, at the price of being mostly unable to cast spells and being more or less unprotected. A suitably not so easy option to use.