I think the point here, if you look closely at the picture, is that there is *no* door. There is a single fixed glass panel at the showerhead end of the tub, but nothing at the other end to prevent water from deflecting off of your body and out onto the floor. The further problem is that in many of these units, they are designed as a "stand up shower" (rather than a tub/shower), so there is no tub spout to work with while getting the temperature right.

Basically, you have to get into the shower in order to turn on the water - which sprays on you while you adjust temperature. If the shower head is high enough (or you are low enough), it can be aimed mostly straight down - which minimizes spray through the open end.

I have run into a couple of these in the US, mostly at "resort" type properties.