You didn't present any of this in your OP though. Almost 7 does not always mean turning 7 on this trip. And I guess it was nice the that CM let you get in the SR line, but the rule is already 7, not almost 7. We are all responding given the rule. You are also the one who said your son cried when separated from you earlier that morning. Nobody thought you were doing to intentionally upset your son, but you did do it knowing it upset him previously. And the point of the SR line is to ride single, not wait until you can ride together. If you must ride together, then you skip the SR line. You are lucky that somebody was so easily & happily willing to change spots with you, but you are asking a lot of other people to assume that would happen.
We can only go by what you posted and your entire post sounded like you skirted the system, both with their ages and the purpose of the SR line.