Forbo, the manufacturers of Marmoleum Click floating floor system claims that their new design for the joints is almost waterproof. The tongue and groove joints are pretty tight and when installed correctly form a snug fitting. As mentioned in the earlier post, they mention if the spills are wiped dry right away, one should not worry about water penetrating through.
However, you raised a very good point. The sheet linoleum just like vinyl, being a monolithic surface acts as a very good water barrier. Even though it is stated that Marmoleum Click can be installed anywhere in the house, one has to be careful while laying this floating floor system next to bathtub or next to sinks where kids may spill some water and there may be a possibility of it going unnoticed for several hours. If your situation allows you to use a “J” mold flashing next to the bath tub or such, that would help keep water from flowing down on the floor.
I came across one instance where we had installed Marmoleum Click in the kitchen for one client here in Bay area. They happened to have a leak in the sink pipe underneath and did not notice it right away. The water leaked through the cabinets, under the floating floor for what seemed like couple of days. The cork base on Marmoleum Click readily absorbed water and eventually the floor swelled with moisture. They actually had to take the floor apart, dry the panels all the way, and re-install after few days.
With such fancy floor materials one has to be vigilant especially in areas like kitchen and bathrooms.