Warning the user about no flow conditions is not inherently tied to the ET function. This would have the same result in a set it and forget type setup as well. However, the OS firmware does have the ability to send messages out when certain alarm conditions are met. If you wish to have an SMS message sent with High, Low or No flow conditions this can be done and is still included in the base firmware. The ET calculation has nothing to do with this function, and has neither removed nor changed its abilities. The one side effect is should the water somehow run longer or less than needed it will adjust in the following days hopefully negating the issue.
As always checking for proper function of the system is still the responsibility of the end user. As myself or any other programmer can not be present to correct physical faults in your personal system. Hopefully that explains things a bit. Please don’t take anything as me being rude but some problems rely on an owner fixing them. If you would like for me to add a “master” valve as a protection to the actual valves running, that is something that could probably be done. Just note that the ET function is not a fail-safe for physical fault or destruction of your system.