set following commands ( first one with repeating command block and the other with chain command block) :
/gamemode a @a[r=5,m=s]
/gamemode s @a[rm=6,r=7,m=a]

active those command block , switch to creative mode then switch back to survival mode , you'll notice that your gamemode stucked to what those command block are set , can't change gamemode even those command blocks are deactivated , only one way to resolve is reloading the world .

watch the video for the reduction