Nah, Lillie's just trying to protect it, but it wont stay in the bag. So, Nebby, stay in the hecking bag.
Poor Nebby is in that bag for how long every day? Probably half the day. Do an experiment: put yourself inside a person-sized (?) duffel bag (or blanket burrito, maybe) for 12 hours of your waking day with no phone or 3DS or anything, your only interaction with the outside world being someone talking to you from outside your duffel. Now do that every day for a few weeks, or however long Lillie is adventuring outside of Kukui's lab. Get back to me on how you're psychologically feeling when you get back, and tell me Nebby should put up with that. Honestly, Lillie should either get Nebby into a Pokéball (which Rotomdex claims are cozy), or find a way to defend a non-jailed Nebby with some bodyguard Pokémon. Less cruel that way.
I would say no, a poké ball would probably be better and is pretty darn obvious Nebby did not wanna be the the bag.
It was okay until they got to Professor Kukui. He should have insisted that Nebby be placed in a Pokéball for its own good; it would definitely prevent several of the shenanigans that happened. Even if Lillie didn't want to be a "Trainer", her taking responsibility for Nebby should have made her having Cosmog in a Pokéball a foregone conclusion.
Yeah, I'm with everyone else here in that a Pokéball would be a much more comfortable alternative. Why not a Luxury Ball even, so Nebby would actually want to stay in the ball?
I'm of the opinion that he should stay in the bag. After all, Lillie is trying to protect him without taking any of his freedom to act. It's only when he leaves the bag that he gets into trouble. If he had stayed in the bag he would have been able to avoid being captured by me and forced into a box. So where's the real prison?
It's easy to release a Pokémon, both in the games and in the anime (well, maybe not psychologically - see the final Butterfree episode), so the Pokéball is not so much a prison as it is a guardian system that protects the Pokémon that a Trainer has with them. Lillie's gentle nature would never have forced Cosmog to remain with her after the threat passed, so while she loves Nebby she wouldn't keep it; her whole travel was to find out where Cosmog came from and help it return home. Plus, as @Zero Sifr said, see how you like being confined to a duffel bag for 12+ hours - especially in Alola's hot, humid climate.
I think it would be better and easier if she caught it then hid the ball in a smaller bag. It would also make it more inconspicuous.
We have yet to understand what is inside Pokeballs, so it would probably be nicer inside of a ball instead of a small bag in tropical climates. Plus, as the guy above me has said, this is more inconspicuous than if Nebby could escape the bag at any time.
Spoiler Hi I'm alive I mean, if we're into the whole morality discussion of whether or not keeping a Pokémon is confined into a tight space--or otherwise "owned" by a trainer or human--or not, then it only seems fitting to point out that, no, Nebby should not stay in the bag. Do not ban Nebby to the bag.
You know, before I would have said yes, because Lillie's trying to protect it that way, but then I saw this on Discord: Spoiler Poor Nebby.
I say no, because Nebby clearly does not want to be in the bag and, according to Rotom, pokeballs are extremely comfortable. Also, it's more inconspicuous than carrying around a moving bag and Lillie carries around luxury balls for some reason.