1. we don't offer tunerlocking on any gen 5 ecm's to my knowledge so if you are looking at locking gen 5's you won't be able to even if you wanted
2. locking them is up to you the tuner, if you lock it and you provide a shitty tune or the customer moves, does more mods and wants it tuned at a different shop be aware that customer will likely be pissed when he finds out he needs to spend another $500 or $1000 on a new ecm because you locked it, even if you tell him ahead of time you are locking it. With that said its a hotly debated topic with us being stuck in the middle, do what you want