Clearly, the only folks who will have their magazines searched for more than 7 rounds will be folks who are already arrested for other crimes, related or not.
Probably go something like my CCL class. We were required to put 10 rounds on target. I was using a 1911 with 2 mags loaded full. We were required to shoot 5 reload and shoot 5 more. I got thru the first five with no problem but lost count on the second mag. Not wanting to have to shoot again I emptied it. When the instructor counted there were 13 holes.7 rounds in a 10 round mag. Thats funny. Those politicians would make better comedians. Cuz thats what they are a big joke.
If you are foolish enough to be caught with a salt shaker or a soft drink larger than 16 ounces, the officer has the probable cause.