If possible, use odds matching software to minimise loss if the horse doesn’t come in the extra place. Or if you have time, use an odds comparison website in comparison with an exchange.
As stated, it doesn’t happen very often, you’ll probably be happier concentrating on other strategies.
I have had a few here and there that I actually made a profit, albeit very small, without the horse hitting that extra place but I will tell you that it’s a great feeling getting them in!