single word requests - Technical term for valid but unusual?

This question applies primarily to coding. Is there a term that describes input that is valid but unusual?

For example: If I ask for a username, and get @##3i7&*(x]. The code should allow this, but it's not within the realm of expected, username-like inputs.

A similar real life example: going to a restaurant alone and ordering 6 of the same appetizers and a bottle of wine. This is allowed, but abnormal.

The word "strange" comes to mind, but that doesn't feel technical enough.

Thanks for the help!