Tbh I could care less who Vendetta has a pact with. Let them do whatever they believe works for them, if it fails well then they are the only ones to blame for that. Seems that they had a poor excuse to kick you out though.
As for this whole Inked Up Trailer Park Trash pact or no pact, it only makes sense for them not to hit each other just yet. They are the two best alliances, they should wait until later in the world to hit each other. If there was any pact between them I would expect that one of them would turn on the other once the other competition is gone. If not then it isn't the first time in grepolis that two good alliances have had a pact together. It shouldn't come as a surprise when it does happen, hardly ever is there an alliance that does zero diplomacy.
No need to be scared of them if it did happen, if your alliances and allies work well as a team then you should do fine against them. If people leave they just lack confidence in their alliance and in their own abilities. That is silly, have fun, try your hardest, and whatever happens happens. It shouldn't be anything to ruin your experience. If they have no pact then all I have to say is why is everyone worrying for no reason then
Note I am not in either of those alliances so please don't get that idea about my post