You know,I thought that when the 100 first found the guns in the first season & started using them against the Grounders,that that was the first time that the Grounders ever saw guns. But the Grounders knew how to stay out of range until the 100 ran out of bullets before attacking the 100(& getting burned to death because they didn't see that rocket engine ignition coming),then it dawned on me recently,they are VERY aware of guns because of the Mountain Men using them against them(the concept of a safety switch on assault rifles & certain pistols might escape them though). It's also very unsettling that the Mountain Men have camera surveillance on both the Grounders & the Sky People & can tell if they are fighting each other..........or uniting together,which would be very bad for the Mountain Men. It would be interesting if the Mountain Men have found a way to recruit Grounders,who would not be turned into Reapers,into both spies & a fifth column for them. The Mountain Men know who the Commander is,& since the actress playing her is also going to be a main character on the New Walking Dead spin-off,will the Mountain Men assassinate her(& ironically have Clarke elevated to new Grounder Commander as a consequence,that'll come back to bite them in the @$$).