I only have one Pad Area, and it's right in front of the Doggy Door that leads outside. The door is not open all the time, and both mine will bypass the Pad and go outside, when the Door is open. There have been some exceptions, when it's raining hard or very cold, they will use the Pad even if the Door is open.
HA, they don't like to be cold or wet, but, they'll jump into the Bayou after a Frog with the temperature at 40
°...go figure ! 