No, not the receiver. This specifically applies if you've sent the file using Adobe Sign.
If you use Adobe Sign to send a PDF to another user, it can be signed from any mobile device and even from a web browser without the need to have Acrobat or Reader installed, nor an active AdobeID.
The receiver's authentication method to view, fill, and sign an document that person's email address and nothing else. You as the creator of the PDF, yes, you need to have a paid and active subscription.
Great. thank you! That's what I thought. I would have to guess that some cookie decided that I had and Adobe Account and tried to take me to my Documents in the cloud where I could sign my test file. Just guessing.