Catch? Out?

[SanDiegoSteve]

And you're still wrong. Notice that there is no distinction between fair and foul under Rule 2.00 CATCH. The runners may leave their bases the instant the first fielder touches the ball. If a the ball then becomes an uncaught foul, then the runner(s) must return.

However, they may leave as soon as the ball is touched, whether in fair or foul ground. Otherwise, the reason the rule is there in the first place would be useless.

The rule is there to prevent shenanigans that outfielders used to pull back in the days prior to the rule. They would juggle the ball all the way in to the infield, so that the runners could never score on sacrifice fly situations, both fair and foul.

By your logic, the fielders could do the same BS manuevers they did way back when. Just tip the ball in the air as they ran in from the outfield.

That is why you are wrong, and everyone else is right.