I might call **anonymously** -- but they can't say no if you haven't asked. Whenever I am going to do something that people might have a reason not to want me to do because somebody else messed up their day or life when they let them do it, I either try to do it so discreetly that they don't even know (which of course means making sure it doesn't mess anything up for them), or in such a way that it is clear I'm taking their needs into consideration.
This is, however, one of those "easier to ask forgiveness than permission" situations IMHO.