I teach an online class, and everybody who forgot to register sends me an email asking if they can get in my online class. If there are openings, I let them join -- first come, first served.
Luckily, all the spots were gone when I got this email:
Good afternoot my name is jennifer mxxxx, iam interesten in taking your web class and iam asked for a signature from you please let me know what i need to do next.
thanks in advance

Then I added a P.S. to her email.
"You may want to correct your spelling and punctuation before you ask another teacher."
Today I heard back from her, "thanks"
No punctuation. No capitalization.
I hope she gets in a class.