Alternative result:
"We won't fall for your tricks, abomination!"
*stabs
Why would they trust the undead monster?
They won't unless we can convince them we aren't evil. Hmm, What to say?
The problem is that we don't know anything about these adventurers. They might be holy and good and benevolent and kind and willing to help us if we're not evil. They might be holy and good and benevolent and kind and racist douchebags on an ethnic purge. They might be greedy bastards an odd-looking brick away from looting the walls. They might be dire villains seeking to ensure that none with the power to oppose them survive.
But until we know any of that, we're not gonna know the right words to get not-stabbed. We'd need to eavesdrop on them first at the very least.
I think my idea would work
Even if it would, we really don't want to alert them to the fact that there are other wights running around. Probably better to just let them take their loot and leave, then find food the traditional way but with less dead weight claiming all the good stuff.
Though on that note, I vote that when we do hunt, we only drain people to unconsciousness. Potentially more witnesses, but much less panic and fuss over the matter. "Oh no, the passout ghoul is coming, hide your children or they'll take an inopportune nap."
And, you know, if we chance upon any homeless drunks that simply
will not learn, this helps ensure that they stay readily accessible and convenient.