Jersey/Undershirt Test Question

[Jurassic Referee]

Freddy brought up a good point in a PM to me....

NFHS Case Book Play 3.5 SITUATION B:
The officials are on the court prior to the game observing the team warm-ups. One official notes that a member of team A is wearing a decorative necklace.
RULING: The official should inform the teammember to remove the jewelry immediately. Upon compliance, the team member may continue to warm up with his or her teammates and may start the game without penalty.

Which brought up the questions(also in another thread btw)...
1) does the same concept apply to undershirts?
2) if the question above listed "jewelry" instead of "undershirt", would A now be the correct answer?
3) Does the player with the illegal jewelry/undershirt have to remove the jewelry/undershirt immediately? Or can the player simply refuse?

It all goes back to what I thought we had to do in that situation. I thought that we couldn't tell any player to remove anything. We could just inform them that they couldn't participate until they removed the illegal item. The final decision was up to the player though. They had the option of sitting on the bench wearing their illegal jewelry/undershirt.

Thoughts(because mine might be wrong)?