What I do find interesting is the timing of all this. I sent MIL an email yesterday (see previous page) where I said that if W didn't want to go I had other people in mind that would. Twelve hours later, W asks if there's anyone else I'd rather take... hmmm. I think she also saw me driving by on the main road yesterday. Might have got her thinking about me. Who knows. might all be coincidence.
Oh I would pretty much assume that everything you tell your MIL gets back to your wife, and act/speak accordingly. Not everything will, of course, but it's the best way to live in any case.