So your theory is that the smoker ran for 4 hours (9am until 1pm), then got unplugged when the garage door closed. And the smoker was off for the next 4 hours (1pm to 5pm). Did your wife happen to check it during the first 4-hours, or at least verify that it was producing smoke? Because at that point in time, your cook was no different than anyone else's. Keep in mind that the best instructions for anyone minding a pit in the first few hours include the option to grab the meat and put it in a pan and move into a 275° oven if they notice a problem with the pit. When the problem is fixed, the meat goes back on the pit.
The primary concern is the temperature at the surface of the meat, and once the surface temperature goes over 122°, the multiplication of bacteria (which had been doubling every 30 minutes) starts to slow down, and once the surface temperature goes over 141° the surface bacteria is actively dying.
If your theory was correct, I suspect the surface temperature was over 141°, when the pit got unplugged. Meaning any potential dangers happened in the next 4-hours.