It was decided for Talia's Luna ceremony to be held this night when the mixer for unmated werewolves was organized.
They picked this evening in order to conceal any possible magical effects due to the bond forming between Talia and pack members.
When a new Alpha or Luna are introduced to the pack, every pack member will feel the bond changing to some degree. Considering Talia's unusual background, they couldn't predict how this would affect members of the Dark Howlers pack.
Another risky variable was the point that Talia was an Alpha of the Midnight Guardians pack, and there were no recorded cases of an Alpha having two separate pack links.
Talia's Luna ceremony overlapped with the event where people will be in high spirits. Unless something extreme happened, people would think that whatever they felt was due to the joy of an unexpected event (like a fair where several packs participated). Everyone loved parties.
Naughty Shaman! <hehehehe>