Often people, especially renters, have a casual attitude about slopping water from a bath or shower onto the floor. Obviously, a tub or shower needs to have a satisfactory surround and, at a shower, a curtain or a door. But there must be a decent seal at the floor, between the tub or shower and the floor covering, so water does not seep under the floor covering.
In checking a tub or shower, the inspector may find damage at the caulking or seal that could allow moisture into the area below. This it the best photo that I have showing the extent of damage that can result from careless use and maintenance of a tub. This was taken at a home in Bellingham.
Once there has been this degree of damage, including rot and a hole in the floor down into the crawl space, this changes from a maintenance issue into a major repair. When people see problems and ignore them or, in the case of tenants, do not report the issues to the landlord, the costs of repairs can go up astronomically compared to ths costs involved in simply keeping up with ongoing maintenance.