When these people registered their MG's, were the local CLEO invovled? Could they veto the MG registration and make the owner get rid of it?
Most people did not know the law even came to pass. There was no internet, there was not a huge amount of coverage, and libraries wouldn't have had books about it for quite some time afterwards.
People were not glued to the rare TVs, and it was the middle of the Great Depression!
Plus on top of that they wanted thousands of dollars immediately to not become a criminal (that is what $200 was back then) if you happened to learn of the new law.
This at a time when infringements were viewed strongly, and infringements by the federal government seen as a really big threat. So a rush to comply was lacking for those who had such firearms.
Put it into perspective: Governments around the world have declared registration before oppressive measures. This was not only registration, but you had to pay thousands of dollars for that registration ($200 then was a few thousand) when most people could barely feed themselves. All with guns the government was essentialy declaring it did not like.
People had no way of knowing they would not simply be taken a few years later like has happened around the world.
So for more perspective:
Imagine if the federal government tommorrow declared all semi-autos had to be registered, and everyone had to pay $10,000 per semi auto, had to get local and federal permission and go through several new steps.
(Keep in mind during the depression
most could barely feed themselves, and people are doing much better than that today in spite of the "recession",
so the cost was even greater than just the few thousand. So you need to adjust the price up much higher just to understand the type of burden it would be to most US citizens. So just the raw conversion of $200 into 1934 currency does not give the full picture.)
How many people would trust the government was not going to just take them all a few years later like in Australia, England etc recently and start registering every semi-auto they owned and pay that fee for each one? Got 10 semi autos? Come up with $100,000 quick!
How many people do you think would hide some, or suddenly lose most of them?
Now imagine no internet, many without TV and radio hardly covering it or failing to mention it on your given station, many without power. A local newspaper might have something mentioning it on a given day someplace, maybe not.
So for those that even knew of the law it was hard or impossible to comply, and should they comply? Was it tyranny, the removal of the Constiutional right? Was it going to get even worse? Was Congress or the President simply going to scrap the Bill of Rights?
At the time FDR after all was essentialy doing anything he wanted and simply threatened to add more judges to get whatever Supreme Court vote he needed on a variety of issues if necessary, stripping existing judges of thier level of power, so they usualy eventualy voted as he wanted. So thier ability to uphold the Constitution was greatly diminished, and eventualy he packed the court in his long presidency with those who favored his beliefs anyways.
The government had been taken over by a Tyrant, the government demanded mandatory registration of the most capable weapons and an extremely high fee when
people were starving, and the average person was not even aware of the change in law.
So as you can imagine, most were not registered.
They became illegal guns. The government allowed for registration a few times after that (they after all would rather know where the guns they don't like are than not know) but in between and after those dates they remained illegal if not registered.