Of course all of the major leagues would say that they are not at all biased. Most probably have extreme suspension rules for being involved in gambling. But, we shall see. Human beings are fallible creatures; people forget, people slip. And it's hard to prove this. Especially nowadays, when you can do it over your phone in private.

Still, it really doesn't matter,

After all, who wins the flag.

Good clean sport is what we're after,

And we aim to make our brag

To each near or distant nation

Whereon shines the sporting sun

That of all our games gymnastic

Base ball is the cleanest one!

https://en.wikipedia.org/wiki/Black_Sox_Scandal