Lots of lights will work with unprotected cells, you don't need 2 springs. Just the correct length battery tube and contacts. Quite a few lights will not work with longer protected batteries.Protected batteries have a circuit that shuts them down when they are being drained too low to save them from getting ruined, and other protections for safety. Unprotected cells do not. Protected cells are also a bit longer and have a button top that make them work in far more types of lights. For unprotected cells, you want a light with springs for both battery contacts or it may not work. Putting a rare earth magnet on the positive end of the unprotected battery will make it work in most lights without springs for both battery contacts. The Nitecore MH10 v.2 has springs for both contacts for 21700s. It doesn’t for the battery magazine for 18650s but still works with unprotected 18650s. The MH10 v.2 also has a battery indicator to test voltage while off and give you an idea of when to change batteries while on. Because of this, it’s pretty safe to use unprotected cells in the light as long as you’re holding or monitoring it. If you ceiling bounce the light overnight on a high setting and fall asleep, that’s when I’d suggest using protected cells.
If you’re worried about something like that, use a light where that is not required, use protected cells instead, or carefully solder a blob or spring on the positive terminal of the cell.Is there any flashlight manufacturer that suggests using a magnet on the positive side to get some battery to work? Thinking no. Wondering if somehow the magnet might shift so that contact with the body and the positive of the battery might initiate some kind of florid expression?