Can a manager or parent request placement of a given player to a given team?
As a rule, no. It creates problems of stacking teams and tends to make assigning players impossibly complicated, since when such requests are honored, many more such requests are made. There are a few exceptions. (1) If a certain manager and a certain coach wish to work together, and combining their kids on the same team will not have an obvious effect on league balance, we will usually assign the coaches and kids to the same team. (Also, we bend over backwards to reward people like coaches who volunteer their time to CYB.) (2) If a child has a transportation problem, well make every effort to assign him/her to a team if someone on that team can help solve the transportation problem. (3) If a child, through no fault of his/her own, has had a poor experience with a particular coach, well certainly assure that he/she is not assigned to the same coach, and well try to honor any request to assure that he/she has a better experience.
