i find this image extremely amusing.

Is it legal for a horse to bet on horse racing?

Probably not in good taste, to say the least... things would probably get awkward.

But people bet at box matches. Also, in some countries you can predict the score of a football match as a bet. They're both completely legal.

Tapper said:

Is it legal for a horse to bet on horse racing?

Only if its her own race, since then she could throw it to cheat on the bet.

Pronak said:

But people bet at box matches. Also, in some countries you can predict the score of a football match as a bet. They're both completely legal.

More, since she is a racehorse herself, she's likely placing bets on her own friends/rivals/etc here. Even if- or rather, especially if- she gets a big payout, that's going to make things awkward if they find out.

Feel like this warrants a Hilarious in Hindsight entry because the bottle of booze in the side is Nanakanba, a sake brand whose owners have ties to the RL Symbolis (and the namesake is indeed Rudolf), and didn't let the opportunity slide.