As a former Rock n Roller Coaster CM I always have to add my 2 cents about height restrictions...
The condensed version- My son stayed 47" the whole year I worked that attraction and he never rode Coaster with its 48" inch limit. Could I have put him on that attraction? Yes.
Would I put anyone I loved on Coaster? Without a doubt. Would I put anyone under 48" on that ride- Not on my life.
The CMs at Disney are very selfish. Why do you ask? They want your kid to live long enough to be brought back for another Disney vacation when he's tall enough to ride and not *heaven forbid* be injured or killed on a ride he shouldnt be on...
As for trying to smudge for the checks- Believe me we've seen it all- from Icecream bars in the shoes to trying to sneek the kid on the ride (individual seats people- Ya REALLY think we're that dense???) to the whole familys socks in a pair of jelly shoes and the whole high hair thing (trust me 2" spikes of hair on the head DONT count" Most of the CMs can judge just by looking if your kids tall enough (not 100% accurate sometimes though- hey we ARE human) and even if by some reason ya get passed the first greeter be advised that ANY of that Attractions CMs have the authority to give your child a height check ie Passin the Greeter doesnt mean you are "home free". Because well if something were to happen we'd be held responsiable...
In the case of an incident your childs 2" padded soles will NOT save them.
The probability that your child would be just fine riding the rides is high but what kind of guilt would there be if they wernt...
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As for the adults that are not at the height requirement- It is a case by case basis. However in my experiance (with NO disrespect intended) at least most of the shorter adults are not as skinny as their same height level kids (as most 48" kids are toothpicks) and so even with the less heighth their bodies fit the restraints better than the kids do but it *IS* the final decision of the manager in charge-
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Okay so that wasnt soo condensed- I tend to get rather passionate towards childrens saftey, Maybe cause Ive had a few of my kids become angels and know how precious a kids life is and missing one or a few rides at Disney will not hurt your kid in the long run-
-em