Correct in that it is PRIA reportable...but that also means that you have to fill out the form and give it to the hiring airline. So they are going to know all about it.

I would say do not put it on your resume...that is intended to highlight your positives and sell you. Since you were only there three weeks, it will not be a glaring resume omission.

But you will have to list it on the application and the PRIA paperwork so it is 100% guaranteed that it will be discussed at the interview.

As to how you deal with it...that all depends on the circumstances. Why did you leave?