It's pretty much an un written rule to never arrest anyone in the little spawn room in air port we wait for them to run out and and start doing stuff, you have a chance to backpack it then but, would u really expect cops to just let people run around with mk 18s in air port and just leave them? Your suggestion to fix the issue is by making the officer tell you to put it away, I feel that will vary from person to person Roberts may do it as he is experienced in cops and rebel so he knows the bore of having your gun yoinked but a semi new prob pc will be all over it and will try everything to take it. Cops generally take weapons from people depending on factors, the calibor of weapon, the peerson holding it and attitude. If you are walking around openly with a big gun (7.62) it'll be yoinked its dangerous and is more powerfull than most cops have, if the officer knows the person with the gun they may be more inclined to ask them to hide it and the attitude of the person well if u are gonna be rude and evasive the officer will take it without hesitation. U also have the chance to roleplay your way out of it, make a story up or make a hunting document or something then u are likely to keep it.