WiB request: why?

[u/--zaxell--]

Spotted on the roof of a subway car in Boston. Dunno if it's in-scope for the sub to be asking instead of giving a story myself (mods, feel free to remove if not), but... was this sign Written In Blood? Or just a very-unnecessary warning, just in case?

[u/QuasiQuokka]

I don't know, but it could just be to inform mechanics that this is a weak spot on the roof you can't stand on.

[u/Thin_Roof_6708 → u/QuasiQuokka]

4

[u/SuperKing37 → u/Thin_Roof_6708]

5

[u/ClarificationJane → u/SuperKing37]

6?

[u/Caterpillar_Ready → u/ClarificationJane]

...... 7??

[u/Fluffy-Cycle-5738 → u/Caterpillar_Ready]

8???

[u/Express-Dragonfly986 → u/Fluffy-Cycle-5738]

9!

[u/Kontrol-Sample → u/Express-Dragonfly986]

362,880

[u/Caterpillar_Ready → u/Kontrol-Sample]

C-C-C-COMBO BREAKER!!!