If we ban porn among the troops due to "cultural sensitivities" you can be sure some commanders prohibit the use of .50 cal weapons at various levels.
There are four different Geneva conventions. I wouldn't be surprised if none of them prohibit using a .50 caliber weapon against an unarmored target. Doesn't mean you aren't told "no" when it comes to using one in combat.
FYI, the Army banning porn is another myth. Sorta. Congress banned the military having porn. Military Honor and Decency Act of 1996, introduced by Congressman Christopher H. Smith (R-NJ), cosponsored by Rep. Roscoe G. Bartlett (R-MD), and Rep. Robert K. Dornan (R-CA). "Family values" types, not "cultural sensitivities" types. Same evil, just a different flavor. The Army has chosen interpreted MHDA in a more strict manner than legally required. Standard CYA.
.50 cal is not specifically banned from anti-personnel usage. In general. Now you have command driven Rules of Engagement that may ban usage of specific weapons for various reasons. Basically staff poultry excrement types that think combat is about action items, power point presentations and getting promotions.
Porn was specifically banned in Iraq - I know. They searched my belongings multiple times and that was listed among the "contraband" items that were going to get me in serious trouble if found. Too bad the Army is so far behind the times when it come to scanning encrypted hard drives.
Bosnia (TF Eagle)/Kosovo (TF Falcon) as well. Hell, porn was forbidden stateside during OIF IV mob back in '05. Brass got nailed for moving porn over SIPRNET. They were eating up 60% of the satellite bandwidth, which honked off the satcom guys. We enlisted just used external hard drives with TrueCrypt. My going rate was $50 per hour per HD, plus a copy of all the porn you had that I didn't. Didn't exactly watch the stuff myself, but it paid very well. Paid a couple PFC's to sort the stuff out by catagory, another SPC to do anti virus scans. A tidy business on a 15 month deployment.
It's a veritable witches' brew of chemicals onboard, too. Think about large amounts of hydrogen peroxide, potassium hydroxide, chlorine gas, etc. There's even an airlock between the laser compartment and crew compartment, in the event that all that laser fuel leaks. The belly of the jet is titanium aft of the wings, because the damned thing farts corrosive gas after each laser firing.
Lovely. Does the crew get hazard pay for that? Not that any amount of money would get me in a friggin aluminum can with enough deadly chems to wipe out half a state. Gods I hope that thing is loaded to the gills with countermeasures...