The thing is, rules-wise I do have power over spirits. Stryker doesn't. He believes they help him out of their own will, and because he's polite and determined. He did insult that particular guy, but he didn't exactly do the same with his agenda. On the contrary - it was said to show respect to the family. He said that he can't believe someone from the family could be that arrogant, to insult them with squatter's pocket money, and treat them like crap. He could come by openly and ask his question. This way he would still hear 'no', but it would be a polite and respectful response.
They were paid to get the package there untouched. Stryker won't allow it - that would be breaking their word, and failing the run. And that would kill their reputation...