My LinkedIn profile lists quite a lot of languages and platforms, but I made sure to not include Ruby there, just because:
1. I never worked with Ruby
2. I never want to work with Ruby because I got fed up with the smugness of ruby developers back in the day so much that I made a promise to myself never to be one of them. Literally anything just not Ruby. I'll even take up COBOL if I have to, in order to avoid Ruby, unless I can justify it as a backup scripting language for small automation stuff where other languages would simply not work. Aaaanyway...

I get this message from a guy:
"""
Hey <Actual first name>,

You got recommended by a person, and judging by your profile you'd make an excellent fit for this company I'm representing who are the leaders in their field, bla bla bla more info on why company is the greatest in the world.
They need an experienced senior Ruby developer for their new web application bla bla bla.
"""

I wonder, if I committed to learn Ruby well enough to pass an interview, faked some Ruby experience in my CV, and they actually hired me, how long would it be until they hang that recruiter for not even reading the profiles of the people he's bothering with messages.