Good advice, Jim............
Further, JEA adds:
Customs and Usage: First basemen often position one foot in foul territory while holding a runner on first base. On the Major League level, this is acceptable and not considered a violation of the rule. The National Association Leagues' umpires are instructed to permit this unless a complaint is raised. If so, they are told to enforce the rule as written for both teams (similar to the "coach being out of the box" type situation).
Defensive players are not allowed to be in foul territory to back-up appeal plays or pitches. No penalty is provided. [my emphasis] The umpire simply does not allow play while this condition exists. If a player refuses to comply, he should be ejected.
Fed requires one foot fair, OBR requires 2 feet fair.
From the NAPBL:
1.15 FIRST BASEMAN PLAYING IN FOUL TERRITORY
Do not insist on the first baseman playing with both feet in fair territory unless the offensive team protests. [my emphasis] If they do, you must enforce the rule as written, but make sure it is enforced for both teams.
Don't go booger pickin' as an umpire........
If the teams do it, they're pickin' their own boogers too....
Just my opinion,
Freix