Matrix Keypad routine

[RussMartin]

I have to ask because I have NEVER seen it done any other way. But is it not just plain good design practice to current limit with series resistors and pull up or down ALL digital I/O's?

This is what I was taught back in the "old days", but there are lots of circumstantial exceptions--there were circumstantial exceptions, then, too, but probably not as many of them!