Postal Employees

When you request to see the union to your supervisor, do you have to tell your supervisor why?

For example A: I want to see the union.
B: Why do you want to see the union?
A: I don't need to tell you.

Do you get in trouble or not if you do this? Because I called the union office and she told me I can but I have a feeling she could be wrong.

You are contractually obligated to give a reason. However that reason can be as previously pointed out, very general in nature. In some cases it may be better if you give an exact answer, as the potential threat of a grievance can encourage a supervisor to fix the issue immediately. For example, you were scheduled for overtime and are not on the list, yet there's an ODL carrier available. In that case, a smart supervisor would be able to correct that mistake immediately. So there are times where is appropriate to be very detailed in your complaint and others where it's more fun to simply make them squirm.

Real life examples are good, but so are exact rules. You need to both know what the rules are and how they are applied, both locally and nationally. That one of the reasons that people on this forum prior to it becoming a cesspool of argument, would often ask posters to provide details, so that answers might be better tailored to their actual situation.