OK Gaseous. You know everything.
Maybe.
Sadly the majority of new pilots don't. There are many things they need to know almost as a sixth sense - and the addition of carb heat in certain conditions is just one.
There are many things that could have caused this pilot to have his accident - he's just fortunate that his failed memory (or lack of training) didn't kill or seriously injure him.
We've all done it - we've all forgotten something.
Putting FI onto the R22 engine is an impossibility.
But educating pilots to follow a well-worn, effective procedure is easy.
It seems to have worked for the vast majority of R22 pilots for 25+ years.