User blog comment:Rampantlion513/Banning the use of certain weapons is a violation./@comment-1990578-20120515000705

I don't know the details on how weapon bans work, but I know that people have at least been able to create a script that detects what weapon you've made a kill with and can take action if server rules are applied. One such server banned all explosives on Op Metro (actually giving the US a fair chance in CQ! who'da thunk?) and would kickban anyone who got a kill with any explosive weapon, even on accident. Shotgun kills also resulted in the death of the perpetrator, but not a ban or kick, only a flashing warning after being killed by admin.

Anyways, my point is that it's likely that many server admins are aware of the M26 MASS with flechettes (or M26 DART, in game) paired on the undersling rail slot with a heavy-barreled assault rifle, particularly the G3, gives it near-pinpoint accuacy in aimed fire and a massive range boost as of Patch 1.04, allowing one-shot kills at long ranges - further out than current Sniper chest OSK's to as far as 25 meters or more (snipers having an OSK to the chest within 15 m, save for the SV-98 at 20 m for whatever reason).

In contrast, servers may not be able to ban a single weapon, but instead punish the whole class of weapons to keep this glitch out of stat padders' hands.