Oh, I think I know!

Connor!! Riggs!!
From my assessment, it appears to be a nerve/marking thing. I only say marking because he knows how to empty his bladder in full (and does so regularly), and the amount is small, as in the amount that would typically be used for a mark. The one we know he definitely did was barely a splatter, much less a puddle.
I think the nerve part because I know him, and in retrospect, that kind of situation might indeed make him stressed, and he had just been a kennel, where the staff specifically told me that he had marked ON his bed (which was his own that I brought for him from home), which he has never done before, and I know he was stressed at the kennel.
I also work for a private kennel, and I know what a mark pee looks like because I clean them up from all over the kennel owner's home all day! Although typically it is on something, instead of on the floor.
I'm just happy I've narrowed down the cause and motivation. So far its the only place I've seen him do this (discounting a few accidents when he came to live with us at only 7 months). We don't intend to allow him to do it again, so he'll have an escort when his "cousins" come over or we stay with my inlaws and they have additional company.
I can only please one person per day. Today is not your day, tomorrow doesn't look good either.
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"You didn't know of the magical powers of the break stick? It's up there with genies and Harry Potter as far as magic levels go." SisMorphine 01/07/07