I think the better answer is to make sure you know before hand who the captain is, the owner or someone else. If one feels comfortable with the owner being captain then do the trip, otherwise find another one.The real answer is to never do a delivery with the owner aboard, unless you're very comfortable telling them they are wrong. It is rare to have a relationship like that. This was a pretty minor issue, the next test gets tougher.
I know people that tow dinghies in open water but I prefer not to for many of the reasons cited here. Davits can be ok if being pooped isn't an issue and the davits are strong enough.