Mechanics
 

NFHS or Asa

Runner on
A)1B,
B)1B & 2B
C)1B, 2B & 3B


Fly Ball hit to Right Field.

On appeal who has the various tag-ups
Most concern with 3B and 2B as in C

I believe it is best to learn the general rules than specific cases. Assuming BU doesn't go out on the fly ball (and it doesn't matter what field the ball is hit to):

PU always has 3rd base, BU always has 1st base. If single runner at 2nd, BU.
If multiple runners, PU always has the lead runner, BU has all trail runners.

Those are the standard rules. If BU realizes a ball hit to right and down the line will present a challenge to PU, then BU can communicate "I have your tag at 3rd". Otherwise, if no communication, the standards apply.

Some may get on here telling you to pregame this; it is poor advice to pregame a variation. Only let a play determine if a variation is necessary, don't preplan to vary.

ASA assuming 2-umpire crew and BU does not go out:

Runner on
A)1B, BU
B)1B BU & 2B PU
C)1B,BU 2B BU & 3B PU


Fly Ball hit to Right Field.

However, the crew may deviate if it they choose to as long as they communicate. Fortunately, a ball to right field makes life a little easier.

Does anyone consider it coaching to announce you are covering a tag up, rather than "switch" or "reverse" or something like that?

The idea of commuunicating with my partners as a form of coaching is new to me

Hell, no. It's preventive umpiring.

R1 on 1B, ball to RF.

PU: I've got 1B
R1: What? Damn, I have to make sure I don't leave early
BU: Out! (R1 was so deliberate in not leaving early, s/he was out at 2B) :D