Another small business owner reported their experience in this Reddit thread, looks really bad: https://www.reddit.com/r/europe/comments/1vrz88a/comment/p4i...
I’m as pro-EU as one can get but that’s a mistake we should solve asap
How would we even sack the leadership?
In fact, if you sell 10 hobby prototype boards to other hobbyists, you probably have a higher risk of getting hit by a bus on the way to the post office than you do of being fined.
Because there's a handful of companies (lectronz, seeedstudio, ebay, etc) that have the full shipment lists. So the compliance agencies don't have to go after individual business records one business at a time; they can go to probably fewer than 10 businesses and find the suggested mass rule breaking with a sql join.
See also the national tax agencies with NACE codes (euro version of NAICS).
That's just an excuse then. Register with whatever local authority in your country handles these things and in the unlikely event you get a grumpy letter just send them a copy of your registration documents.