There's a clear reason why they don't want to waste their time chasing other banks in recovering your $100 that you sent by mistake and instead warn you to check everything.

The point is they know a transfer cannot be reversed, especially when the money has been spent already.

Even a bank who sent out £130M [0] in error to multiple people still cannot recover all of it after 4 years.

[0] https://www.theguardian.com/business/2021/dec/30/santander-b...