This is 'switching' aka 'fighting with no reload'
http://www.youtube.com/watch?v=Rmc1F40lleAI've also noticed people getting confused on this issue.
Now, Shooting 4 sawns/shooting 100tecs then reloading sawns and shooting 4 again is how I fight and how I have fought since learning fight in LW. Never been kicked or reported as far as I know, and its how alot of regulars fight.
I also don't see the big deal in to reloading uzi unless you plan on using them for the while fight.
People also shoot 4 sawns,reload, use Uzi and then shoot 4 sawns, nothing wrong with that but people have been reported for it :/