Is sending an employee a message they've elected to receive ever spam in some sense? If the reflection were to an arbitrary number then I'd say so, but simply forwarding to a specific number you're working with seems... Fine. Maybe it's different too if it's a solution you're selling, but even then that's somewhat between you and the customer.

I guess if twilio has negative impacts as a result of the perceived spam then that's a separate issue.

It was only spam on the inbound leg. On the outbound leg, it was requested and correct content.

I'm already using a spam detection API. But remember those things don't block all spam.

Also, there are other ways to solve this specific problem given that they are intent on auto-suspending my account in this type of context. I could relay the messages using a different platform as an example.

Thats not really the point though. Me not paying for the spam API or not using it when I relay messages internally to employees is not a good reason to shut my whole business down and not give me a way to contact them. This should be obvious.