At the moment, the Mega Torch does not prevent a village siege.
This is due to missing Events in the VillageSiege class, so we will need a PR into forge or a coremod.

Current iteration of torchmaster uses the event, but its hard to test since there is no option to force a siege. Idling for a few hours above a village didn't trigger anything.

MC 1.14 adds pillage events. Once Forge starts on this, we should take a look at how mojang does those siege events.