I probably would, but who leaves a whole bag of money lying around...Sure, I would expect that they have a right to protect proprietary information.
Would you return a bag of money that you found?
I'd probably be scared that the owner is a criminal, and that whether I return it or not, my life would be in danger.
Would you go on a date with a married person, if he/she told you he/she has an arrangement with her partner that they both can see other people?