Originally Posted by
LapLap
You clearly don't have a Japanese (or Korean) rice cooker.
You never, ever open the cooker when making rice with them (they need to build up steam, losing it is disastrous for the cooking process). Japanese rice cookers also have a set of layers beneath the lids - cookers from other parts of the world often have glass tops, but these same cookers are more prone to over-bubbling and scorching rice.
You probably don't remember (or possibly were alive to) but the National (Panasonic/Mashushita) rice cookers from the '70s were like you described. Just a simple aluminium lid with a glass insert sometimes.
Never had a problem as the control mechanism was simple: Heat to ~100C and turn itself off as the temp sensor went over (indicating water was all boiled off).