Just to reinforce what others have said - The days of leather straps and metal buckles usually came with overlong straps. Even cut down there was generally an inch or two sticking out from the buckle. This gave rise to the possibility of the ball flicking the loose strap-end and the sound could be enough to suggest a nick on the bat, if they were on the outside. The current style of Velcro straps (so much easier, quicker and more comfortable) generally do away with this issue as the gripping area does away with the need for straps overhanging the edge of the pad. I tend to stick with told style of strap-end on the inside of the pads, but don't think it matters either way. The whole question seems to be a hangover from the previous era of pad straps.
David