The grammar school I attended had lads from Warrington, Leigh, Swinton, Salford, Oldham and Rochdale. The only winter sport played was RU. Most of the kids wanted to play league, and one of the teachers (not a PE teacher) decided to start a league team. This was almost immediately vetoed by the head. In later life I learned from one of the teachers that the RU authorities had informed the head that if they had a league team at the school, no player would be considered for RU representative matches. I'm sure that this school would not be a unique case.
The tragedy is that three of my contemporaries became full RU internationals, two of whom would have been natural league players given the chance