Here a link from a German organization of self-employed people that informs about the current situation and what is planned (it is planned to worsen the situation): (sorry, only in German)
http://www.vgsd.de/kampagne-scheinselbststaendigkeit/
The big corporations, of course, which really use different models to betray the social system and their employed people, they have the lawyers and the tricks to come away with it. And again, they are the reason for this hunt ... because they are searching for ways to cut costs -- the state tries to close the holes that make such things possible -- but currently the only people they hurt, are those that are innocent, because the big corporations are always ahead of the game. And additionally I am not sure, if the politicians are really willing to hurt the real big players, because those have so much power -- so they merely show "actionism" and make laws that are ineffective or even hurt innocent people.
At the end (if by intention or just stupidity), they hurt the country ... but we Germans still vote for those people!
One fiscal year can be very short in the IT sector. In some cases, you need halve a year to get to know the complete topic.
According to the link I have given, at least in Germany the situation is now such, that even when you have more than one customer in a year, you can be accused to be "Scheinselbstaendig". The offices just search for evidence that you might be, but not for evidence that you are not. One such evidence for "Scheinselbstaendigkeit" can be for example small investment needs ... something you typically have in the IT sector as freelancer ...
It seems that the new law in preparation shall codify this practice.
But of course, when the situation is better e.g. in the Netherlands, it could be worthwhile to work there. But (since I already thought about that possibility) would it also be possible to do so without moving there and still earn the benefits?