depends on your 'device'
at home, you do what you want, it's your responsibility
some specific (industrial, medical, automotive...) may impose battery protection by design, tested when validating the device in labs
to be clear, no protection means first assembly line tech coming Monday head full of Sunday bear will explode the battery. I saw this in one facility, i explained the hw designer battery protection didn't cost that much for industrial hw, he implemented it. of course i don't say this make 100% sure battery usage in the real life, but if done correctly expands battery life and safety. more intelligent people than me analysed this and this was the final conclusion, every battery with some power inside should be at least have a resettable fuse. 18650 is no little battery, everyone advise to handle with care li batts
generic q, generic a