Having worked in luxury hotels for 20+ years, I think you will find that in many regions the bathroom water consumption for larger/branded hotels is a very small part of their utilities costs. The kitchens, plant equipment/back of house is where the biggest consumption is usually found.
In my experience, international hotels may use a device that comes with the bathroom fittings to keep water flow consistent. If the water flow is much lower than that it is usually either a infrastructure issue or someone has gone too far trying to control it.