Just my opinion, but I won't ride on a plugged motorcycle tire except to get far enough down the road to have a new tire mounted.
Given that the original puncture didn't cause a rapid deflation but more of a slow leak, I figured that any failure in the plug would put me back in that situation, and that I would have time to notice the drop in pressure in the tyre before anything critical was likely to happen.
I inflated it a bit more than normal, to make it ride quite hard, and periodically rode over some inconsistency in the road surface, or a glued-down reflector, to test the feel at the back of the bike.
As time went on, I became more confident that the fix would hold up all the way home; if the plug could hold the pressure for one hour, then two, why should it fail after three? It's just pressure, and the plug knows no difference.
I see your concern, and share it - after all, the tyre is now away for a proper fix; I don't propose living with the plug indefinitely - but I didn't take the Isle of Man approach to my ride home, and if there had been any sign of deflation I would have stopped and dealt with it. There wasn't, and I was both surprised and pleased to get all the way home without another stop.
You wouldn't do it that way? Fine with me.