No, for several reasons:

  1. If pipes are installed properly, they don’t plug up.
  2. Plumbers report, that the reason for plugged drains is almost every time located in the trap. Sometimes the hair build clusters that reach far in the drain pipe, but the starting point is always an obstacle under the cover or inside the trap.
  3. By the use of Freilauf, the general amount of hair in the drain system increases not much. Other drains don’t catch all the hair. A clean conventional drain lets pass up to 90% of the hair. This number decreases with the amount of hair that collects. Besides that, shower and washbasin are not the only source of hair. A lot of hair end up in the drain system via washing machine, and toilet
  4. The washing machine puts a lot of hair in the drain, it is connected directly to the pipe, without any obstacles. No one ever heard of pipes plugged by hair out

  5. Most people take the hair out of the shower and throw them into the toilet. So, after 5m they are in the same pipe again.

The Freilauf drain valve can be intalled in all common waschbasins with overflow.

The Freilauf shower drain just raerely fits to an existing shower tub
The Freilauf is a complete siphon/trap not just a new lid. The Freilauf base has to be installed underneath the shower tub. With existing tubs this is normally not possible.

No. Freilauf contains 8mm and 9mm magnets. The magnets are too small to be a danger. The recommended safe distance to a pacemaker is around 20mm.

Iron, solved in water is nonmagnetic, also ferruginous dust is completely oxidized and therefore nonmagnetic. Problems may only occur if somebody worked with iron and carries iron particles in the shower. Iron particles will stick to the magnets and larger amounts of iron particles in the drain may cause the cover to not stand strait any more. But the magnets are arranged in a way that the force of the upper magnet in the cover is a little stronger compared to its counterpart in the base. So, ferromagnetic particles stick to the cover and can easily be removed.
However, rust is a very good colourant. Therefore, over time rust stains will appear down in the drain, where the magnets are located.  This is no defect in the product.
By the way, rust stains can be removed by putting some coke or vinegar in the drain and letting it sit a few hours.

No, modern neodymium-magnets have a constant magnetic force for several thousand years.

We use ABS, a plastic that is used in the fields of sanitary and wastewater for decades, it proved to be resistant to all common chemicals.