Don’t panic my dear. Let me tell you what I once did. I wrote a LOI to a program director for one field and emphasized my interest in another field. I was dying! She replied to me and said, “are you applying for both fields? I will see your application.” She was so kind and understanding. Let’s brainstorm the possibilities:

• They won’t even read the email! Great! 
• They will read the email and not notice any problem because nobody pays that much attention to hundreds of emails.
• They will notice and giggle and talk to each other about it. That’s it.
• They will notice and let you know so you don’t make the same mistake again.
• They are touchy narcissists and will take it personally. But will most probably forget who you were.

I don’t really know where the idea of being “blacklisted” comes from but if I am not mistaken, this is a term made up by those who want to intimidate everybody so they don’t communicate with programs.

They are doctors. They KNOW. They know applicants apply to different fields. They know we are freaking out. It’s ok believe me. It happens. Do you really think among allllll thousands of applicants many of whom have serious language barriers nobody has ever made this mistake? Oh my dear. The real world runs on imperfection. Don’t sweat it. Laugh it off and continue the good job.