Let`s assume we have a mission that involves a tank. Let`s assume tanks can be parked normally into player garages.
1. If I can go with the tank at any time during the mission to my garage and park it normally, just as I`d do with any car - go in front of garage then get inside automatically - that`s normal usage of game mechanics. Not my fault as player because Rockstar didn`t "cover" this option I might take inside a mission.
2. If I go with the tank at any time during the mission to my garage and park it in ANY way that is not going to the door then getting teleported to the garage - that is glitching. Glitching is cheating.
Common sense dictates that, as long as I am using NORMAL and REGULAR game mechanics, Rockstar will not touch me. And going with a car at ANY time, even inside a mission, to my garage and enter normally IS normal game mechanic . It is up to Rockstar to identify potential ways of doing missions differently than their in-house testers, not me. They cannot hold me responsible for what THEY didn`t found out / didn`t think.