Have the seller take a photo of some piece of the equipment with a hand-written (not easily machine scannable!) email address visible in the picture.
It seems that only the seller can write his email in a photo, while the buyer cannot
I remember how a seller got around this restriction by writing in the item description what to search for on Google to find their email and phone contacts
Terms of Sale
Feel free to email or call us directly Mon-Fri 10AM-5PM EST.
You can find our contact information if you google [...]
Well done
Unfortunately... the seller I dealt with is a private.
d'oh.
You just have to make what you write readable by a human and not the machine.
I tried everything: I avoided writing "I attach my contact" or similar, I avoided any reference in the text I wrote requesting further documentation, and I wrote in pen on a sheet of paper, in italics, removing the @, removing dots ... and yet .. eBay's AI always understood that I was secretly attaching a photo with my email address
but I really don't understand why(1) eBay allows you to attach photos, but not PDFs.
I didn't want to bypass eBay, also because it offers a convenient international shipping program, which saves both time and money by anticipating import taxes, I wanted to be able to carefully examine the documentation of a rare SBC before spending more than 200 euros!
(1) If it's for their AI, what's the difference between analyzing a photo and understanding if it contains contact information, or analyzing a PDF and understanding if it contains the same type of information? Indeed, a PDF containing text fields, or images, should not make any difference, in algorithmic terms!