[AtlUmpSteve]

This may be an unpopular stance, and there is no exact rule support, per se. But, one minute was selected as a reasonable amount of time for (both) teams to change over, and prepare for the opposite role. The team leaving defense should have same one minute to:

1) leave their defensive positions and go to the dugout,
2) remove defensive equipment (catcher),
3) take a swig of water,
4) get their bats, helmets, put batting gloves on,
5) take a few practice swings,
6) coaches have a few words,
7) base coaches move to their coaching boxes,
etc.

It so rarely happens that a team hustles out every inning as a normal pace of the games, that I have no sense of special urgency when they finally choose to just because it now benefits them. If the opposing team cooperates, fine. If the opposing team makes a special effort to delay, I will address that. But one team just now deciding they have an added incentive to get started, well, I'm giving the opposing team a reasonable opportunity to get ready, similar to what they have had all game long to this point.