So, a mage of the Pentacle and a Seer of the Throne meet in a bar.
I know this is very subjective and depends on a lot of in-game and character factors. Let's just assume that we're talking about Jane Pentacle and Joe Seer (or Joe Pentacle and Jane Seer, or Joe and Joe, or Jane and Jane, sex shouldn't matter, even though it could, obviously.) Let's say they're both archetypes of their orders, and their powers are of the same level. They both know of the other's affiliation, but do not know each other personally. Their factions are equally strong (or weak) in the city where they meet.
What's the most likely outcome of their encounter? How are they going to react, officially? Do they attack each other? Enter a debate? Call for reinforcements? Eye each other with seething antagonism but do nothing?
As I've said, I know this depends on many things: world, character, story etc, and is, hence, impossible to answer unambiguously. What I'm looking for is the officially most likely scenario, supported by and derived from quotes from the Mage: The Awakening series.