I see foregrips on M4A1’s, but no mags. Army doesn’t use MP5’s unless they are SPECFOR. But I’m sure they’ve got mags with them. It only takes 1-2 seconds to pop a mag and chamber the first round.
I saved it on my HD and zoomed in. I think you're both right. It also doesn't encourage confidence in me that neither are wearing tactical vests or ammo pouches. I suppose both could have magazines in their cargo pockets.
If you're holding a weapon, you become a primary target in an attack - a threat to the attacker. If you're a primary target in an attack, it's seems foolish not to be able to return fire if fired upon. It's common sense to me.