Thanks for the advice guys, the only reason I asked is because I have this vague recollection of taking the eldest to a game against Chelsea when he was a toddler and i'm sure that because he sat on my lap we didn't pay for him. I'll call them and double check
I think you are ok up until age of 4.
We took our Tom everywhere and only ever got checked at Old Trafford and Middlesbrough but just moved turnstile. Once at QPR away, Villa said there were no child tickets (he was about 5). We reluctantly paid the adult price at the TO.
On arrival at Loftus Road, there was a cash turnstile for kids. Took him to the adult turnstile and the bloke said 'lift him over mate'. I sais 'thanks, but he's paid so he's going through the stile'.