As a parent who has used Child Swap extensively for years with my two kids, we have ALWAYS been asked to see the child before they would issue the pass and a few times they did measure to make sure he was too small. Since I still have a 21 month old, we actually are using child swap to our advantage to get around tiering at Epcot and DHS. So there are some pretty significant advantages to it that would very quickly be taken advantage of especially in tiered parks if they let anyone who was "scared" use it. I just don't see that happening except on very rare instances. Before I get flamed though (for using Child Swap as a strategy to get around tiering) please understand that this is NO picnic for anyone except my DS8 because whichever adult waits with my toddler will pay dearly, trust me

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.