When my son went to Aberystwyth University, he played for the American football team. One year they got to the final of the college bowl against Loughborough.
Along with many other parents etc. we went along to support.
A young man, clutching an armful of Welsh flags, thrust one into my hands. I pointed out that although I was supporting the Aberystwyth team, I was in fact English, well Anglo Italian to be precise.
He laughed and said it was allowed, as it was a special occasion.
I duly waved the flag a yelled along with the rest, although I didn't really understand what was going on!
My son along with the rest of the non Welsh team members was drilled by their Welsh colleagues to sing the Welsh national anthem in Welsh. It was magnificent!
They lost, but they sounded good.