Water Damage in the Bathroom?

I recently read an interesting article by Tom Todd of Bay Bathrooms. He mentions that bathrooms are naturally prone to water leaks, which can penetrate behind walls and under floors. When I am looking at homes that we are preparing to sell, I often see telltale discoloration around the base of the toilet or tub.
Todd gives three rules of the thumb with regard to bathroom water damage:

#1. If you think those discolored stains and blisters along the caulked areas of the tub or tub-shower are leaks, you're probably right.
#2. What you are seeing is probably only the tip of the iceberg in terms of water damage.
3. If left unattended, the damage is likely to get worse. Water seeps into the structural wood and promotes the growth of destructive fungi, which thrive on temperatures between 40 and 100 degrees, your typical bathroom environment.

Several years ago, we had a terrible situation when the sewer backed up into our shower, master bathroom and bedroom. The Homeowners Association sent out "specialists" who cleaned the mess, replaced the bedroom carpet and placed a huge machine in the bathroom for three days to absorb the excess moisture.
It wasn't until we removed the baseboards several years later, as part of a "minor" bathroom remodel, that major fungus damage was found in the wall, extending behind a relatively new shower. Our minor remodel grew into a very expensive one, involving replacement of walls and the entire shower.