OK, so the IBJJF says you need to compete at the belt you've been awarded. However, the IBJJF doesn't recognize the green belt as an adult belt. What belt should they compete at? They aren't white, they aren't blue....
Keep the green for the kids.
Green belt on an adult is absolutely a white belt. 
If you were a 15 years old green belt and turned 16 and wish to compete in the Juvenile division, your instructor must then promote you to a blue belt. My son just turned 16, he is a green belt in BJJ and a purple in Judo, he will be promoted to a blue belt.
There is no green belts for adults in BJJ.
In my school, since I teach Judo and BJJ, you will see adults using a Judo green belt, which makes them a BJJ white belts.
Make them fight in the kids division so everyone can laugh at them.
i have seen kids go straight from green to purple. A green is(kid) is far beyond a white belt.
In keeping with the slow promotion philosophy of BJJ, Green is an advanced Belt for kids and you would generally see some pretty significant skills by adult standards from a Juvenile Green. Otherwise, the kids will spend a lot of time in Gray, Yellow and Orange. A Green Belt 15 year old should probably be ready for Blue at least by the time they turn 16.
On the other hand, ATT, Popovitch and Robson Moura among others... use a Green Belt for Adults as a Half way point between White and Blue. For adults, it is an "in house" rank that is still classified as White for outside Tournament comps.
I used to think that Kids Green and Adult Green were the same until I ran into a 15 year old Green who was easily a Purple by adult standards.
But of course, every school is different.
Green is a serious belt. I've seen green belt kids fuck up blue belt adults. We've got a light weight green belt who gives everyone up to brown belt a hard time. IMO, a green belt generally converts into a blue. Only in exceptional circumstances will someone go from green to purple. He/she have got years to grow into their belts, so why hurry them.
James
I think this thread should be directed at the gyms that have added the green belt into the adult curriculum. I know ATT has included it.
I know a guy who competed at white belt at the ADCC trials and won. He is a green belt at an ATT affiliate. I think the dilemma is whether a person like this should compete at white belt or blue belt.
if someone is promoted from white, how can they still be considered white?
Analogy (not sure if it's a good one):
let's say you are 19 and you have a birthday and turn 20. you are not an adult but there is no way you are a teenager. being a "young adult" still does not quality you as someone who could be considered a teenager. therefore you are an adult...just like a green belt should compete at blue belt.
why are gyms freelancing with belts
Really simple. Adult green belts have not been promoted to blue so they have no right to compete in that division. They must compete as white.
Archie Graham -gusto - why are gyms freelancing with beltsEnd your sentence with a question mark, fucktard.
okay?
And I agree that kid green belts can be incredibly tough and many times go straight to purple. They may have been training 10+ years.
"Really simple. Adult green belts have not been promoted to blue so they have no right to compete in that division. They must compete as white."
But they aren't white belts either...
totaldude - "Really simple. Adult green belts have not been promoted to blue so they have no right to compete in that division. They must compete as white."
But they aren't white belts either...
Yes, they are... and any BJJ school using Green as an adult rank informs their students of this. I had a Green Belt from Jorge Popovitch (Pablo's Dad) back in 1997-1998. There is no ambiguity within the school. Going to a tournament means competing as a White Belt.
shark tank - if someone is promoted from white, how can they still be considered white?
Analogy (not sure if it's a good one):
let's say you are 19 and you have a birthday and turn 20. you are not an adult but there is no way you are a teenager. being a "young adult" still does not quality you as someone who could be considered a teenager. therefore you are an adult...just like a green belt should compete at blue belt.
Uhhhhh... not only are you an adult at 18, you are eligible for Adult BJJ rank (Blue) at age 16.
So, I am not sure WTF you are talking about...
Just out of curiosity...if a school does use the adult green belt as an in house rank, do they also do stripes on the white belt, or only senior belts, or no stripes period? <--- didn't want to miss the question mark 
Archie Graham -gusto -Archie Graham -gusto - why are gyms freelancing with beltsEnd your sentence with a question mark, fucktard.
okay?I was just yankin your chain brotha ;-) we good, we good.
i know?
do they charge for the green belt?
I trained under Mike Yanez of Popovitch lineage. When he gave me a green belt I was told it's the same as a 2 stripe white belt. I after a few year I also got my blue under him. He never charged for promotions.