We had a good many responses to this question that showed a great variety.
During 2015 we had these suggestions from Squirrels class in Meadowbrook Primary School who said

 We have some ideas:

We think the class who sit nicest in assembly will go first to break.
We think that the person who sits at the end of the row will go first to the playground.
The person who sits near the door might go to the playground first.
Livvy thinks it will be a girl because boys get sent back because they are running!
Elbadri disagrees because he can walk super fast in a stealthy way and not get caught!

We hope you like our ideas!
Mrs Barbour and Squirrels class

Thank you very much for these interesting ideas.

We had Ajit from Visakha Valley School in South East India remarking that;

1. If the child is a boy then he jumps in the playground with joy. He thinks what will he receive as a prize.
2. If the child is a girl then she runs around the playground shaking hands in the air like a fan.  
 

We had Freddy from Bansted Junior School (UK) who said that it would be a child who finished his work quickly.

Other responses took into consideration their own school special circumstances. So for example, James from Loughview School in Belfast (Northern Ireland), wrote;

The answer depends on the day of the week because each day a different group gets sent out first. It also depends on whether the other class comes out before our class.

Also considering their school was Aaron from St. Munchins in the Republic of Ireland who wrote;

I think it is Calvin because he is sitting next to the door.
The fifth class teacher always lets her class out on time.
I also think it is a boy in fifth class because they are the first class upstairs so they have a better chance of getting out first before any other class in the school.
The majority of the class has dark hair so it is most likely to be a boy with dark hair.
I think it is a boy because we are excluding girls because it is an all boys school.   
 

Henry from Moulsford on Thames in England thought about his school situation and said;

I think it might be a boy in 3c because they finish early and race off. It could be Toby because he always likes to be first. The first boy in the playground won't have had his drink and biscuits.

Ben and Niall from Pownall Hall School in England gave it some hard thinking and said;

We thought of lots of ideas about who would be in the playground first.
We wrote them on pieces of paper and then we put the ideas in order with the most likely one first.
Here are our ideas:
1 It may be a person with the nearest classroom.
2 It may be someone energetic.
3 It may be someone who is a quick worker.
4 It could be someone who knows when breaktime is.
5 It could be someone who wants to start playing.
6 It could be someone really quick.  
 
 

Well done to all of you who sent in your suggestions, I am sorry there is not room for them all. They all showed good thinking around this question that required no arithmetic skills. Please do keep trying the challenges and sending in your responses.