This could be a legitimate use of the Rider Swap pass though. If the two kids riding are both tall enough but not yet 7 when they can ride alone, then the only way they could ride is with an adult. If it's a ride that mom can't ride because she's pregnant (likely, since Rider Swap rides are ones that have height restrictions and therefore the bigger rides that would have pregnancy restrictions), then the only way for both kids to ride would be to ride with dad. I can see a CM allowing Rider Swap in this circumstance.
I can't think of any rides that wouldn't seat one adult and two children unerring the age of 7.
He loves rides and is not happy when he can't participate. I also have very tall kids so they will hit the heigh requirement very early for some rides they may or may not be ready for maturity wise and we will be in "doesn't want to ride but tall enough" boat as well once he turns 2 and hits 40" (he's close now and my older DS hit 40" at 2 year 4 months). I still do not think the policy should be for kids who make the height requirement though.