Now let me make this more clear what are these "gentlemen" doing here.
The RF troops (most of those who we have seen are probably Spetsnaz) entered Crimea for controlling the situation and securing some objects.
Objects secured for now are: Belbek airfield, Navy headquarters in Sevastopol, border troops HQ, AA center in Kerch, border checkpoint on ferry docks and some more minor objects.
The troops secured them quickly... and gently.
The only target of this mission was to prevent any tough guys from messing around with guns, whatever if on their own will or someone else's order. This security is needed to stabilize the situation and provide conditions for the referendum.
The first operators to act here were the officers of the disbanded Ukrainian Berkut force.
Also, more Russian "tourists" arrived on GAZ Tigr armored cars, now with plates. The 21 digits tell they're from the North Caucasus Military District. The Ground Forces, not Marines.
And this Kamaz belongs to the Black Sea Fleet (plate code 90), so the soldiers are the Marines (aka Naval Infantry).
Aww, real gentlemen.
An old AKMS on the right?.. Hmm...