“All dented cells or batteries with dented cells should
be disposed, regardless of electrolyte leakage.
Denting of sides or ends increases the likelihood of
developing an internal short circuit at a later time.”
http://www.whoi.edu/cms/files/LithiumBatterySafetyGuideSG10_26006.pdf
Don’t leave them where a fire or chemical leak would affect your family.
Yeah, it’s not all that likely to happen.
Bigger risk with cheap batteries: Disassembly of cheap 18650 battery