SteemCreate allows for invalid account names

To my knowledge, a valid account name on Steemit starts with a letter, may contain lowercase letters, dashes, or numbers, and ends with a letter or number. It doesn't look like SteemCreate is properly erroring out on non-alphanumeric characters.

The following shows an error to the user on the Steemit Account Creation workflow:

The same username doesn't show an error to the user on SteemCreate.

I didn't try to sign up for an invalid account but I can't imagine that would be a good use of $45.

Thanks for reading!