[Ahnya]

Handicap toilet exclusive for handicaps is it?

To me , I see it as handicap enabled.  Ans priority for handicapped.  But if no handicapped around , others can use , but make it quick , in case one does come along.
Similarly for the reserved seat . Others may sit but they should keep their eyes open to see if an elderly/ pregnant/ etc steps into the carriage, and offer their seats. 
(BTW I'm not saying this cos I want to steal the seat from old folks.  I am PG)

And IMO , the need to label certain seats as reserved is actually a sad reflection on the general attitude of residents here.