You cannot dispatch this problem to the mechanical engineer!!! If the user / operator is going to be able to use the product by pressing buttons then it is also possible to force one of the button presses via an external force from some non-operator object. The pressed button will often represent 10, 100 or even 1000 times the current draw over an unpressed button. As I said before this is a significant issue for portable equipment and with care it is possible to work this one out with a combination of hardware setup and software. (One concept is to have keypad bias for soft turn on be 10x smaller than the power down current you are striving for. Another consideration is to ensure that soft wakup occurs on the transition of the pressed switch only and then fix things so that when you power down with the switch pressed already that there is not an immediate transition generated which would lead to the cyclic soft power on.

Michael Karas