In Ontario specially qualified electricians are permitted to cut the seal and replace the seal - and sign their own inspections. They are spot checked - and an infraction can kill their special exemption.
I have replaced panels hot myself - an emergency panel replacement on the weekend when no POCO guys available to remove the meter - and no permit pulled (got to cottage, turned on the heat, and the main breaker fried - no replacement available for 2 weeks or more, so went to the nearest home supply and picked up a new panel. Working with flashlights at close to freezing temps, we had the lights and heat back on in under 2 hours