I wonder if the cheap Chinese 18650 batteries that claim to be protected are truly protected?
Between a cheap generic one labeled "protected" and a name brand that is not protected, which is more reliable?
"The PTC may not be present in high current cells and it may also be missing in cheap cells."
lygte-info.dk/info/isMyBatteryProtected%20UK.html
So it also depends on how you use it and whith which charger you charge it.
You can have luck with cheap cells.
When it's about sefety, i wouldn't take any risk.
Good protected cells are Keepower.