they do in vdr-portal.de ... as I already do remember a bunch of users still using that function and the reasons why, so no what-if-scenarios.
Not sure why you didn't mention that earlier but aside of that it still doesn't answer this part: "I'd like to know why they don't just use a switch. Simple, cheap, easy, and no complex code required."
One of the main purposes of a switch is to feed multiple tuners from a single cable so it's not like device bonding is a vital feature. The pros don't seem to outweigh the cons but if enough people actually use it it sounds like Klaus will take it into consideration.
-Derek