Another consideration to think about......for portable equipment is can be possible for a user to put the equipment someplace where a button gets pressed down and held there. (Envision a golf course remote sprinkler valve controller that the course tender throws on the seat of his cart and then thrown more stuff on top of that.....a button can easily be squeezed into the pressed position>. You want to ensure that this pressed button does not accidently jump your standby current from 20 uA up 20 mA. ALso make sure that a held or stuck button does not lead to a cyclic power on / power off.

Michael Karas