The fear people have about "mandated proper training" is that because it could end up being a byzantine mess of forms, stamps, classes, fees and time restrictions that it will become just that.
It'll be just like Jim Crow era Literacy Tests. A way for them to approve or revoke a citizen's rights based on the whims of the tester.Yeah, it'll be used to frustrate otherwise legal purchase by qualified people:
Oh, you can't buy a gun until you pass the training course, and it's full, for the next 5 years, you can get on a waiting list, but that costs a $30 filing fee, you must pay and re-file every year of the wait or you're off the list, it's nonrefundable if you change your mind or move out of state, and the training center is 140 miles away, and the class is broken up into 4 sub sections, scattered over a week, and if you miss one due to illness/work/whatever, sorry, gotta reapply.... if you move or change address in-state at any time during the year, you must reapply. If your marital status changes, you must reapply. If you are unemployed for more than 30 days, you must reapply, The following list of petty misdemeanors including speeding, parking tickets or disorderly conduct immediately and permanently disqualifies you. It will only qualify you for one specific make and model of gun, you must retrain for every gun you wish to get licensed for. You may not train for different types concurrently. No, you aren't exempt if you are a former service member or LEO with training, non-state training does not count. And if you pass it all, that just qualifies you for a psychological fitness evaluation, which is performed at only one location, 150 miles in the other direction, it costs $500 unless your insurance covers it, and it won't... etc etc etc
This is why the 2A says "SHALL NOT" , otherwise this kind of stuff would've been ramrodded through years ago.