I wouldn't see an issue with it, if I hadn't had an ex-H who was a gambling addict. Used to spend the mortgage money, steal from me etc to gamble. He phoned me this morning to say maintenance will be late (again) as he has no money. On the verge of being kicked out of his house due to non payment of rent.
This is something that should be seen as a bit of fun, but I have had to have quite a few conversations with my DS, who is 8 about the dangers of gambling, as he has seen first hand the misery it can cause, when I have had to pick him up from his Dad's early due to there being no food in the house or no electricity.
I know my case is probably extreme, but I have taught him that gambling is not a bit of fun and is an extremely stupid thing to do. I think it hit home, when I set up a bit of gambling on football. He thought it would be fun, so I got him to bet me the result of a particular football match (including scores). He placed a £10 bet from his own pocket money and we worked out the odds. If he was right, he got £13 back, if he lost, he lost his money. To really hammer the point home, he lost, so I took his £10 note into the garden and set it on fire. Suffice to say, he thinks gambling is a bloody stupid thing to do now.
I wouldn't judge others for placing bets for their children, it's non of my business, but for my DS is is a huge No.