To be sure, you could add aria-hidden="true", which I'd guess most bots don't recognize.
If it doesn't, its a bug in the screen reader.
I wonder if bots are smart enough to figure out aria-hidden="true". Possibly empty it out using javascript on submit. I would guess a bot not using CSS would also not be using javascript? Unsure, would need testing.
Disclaimer: I don't know how a screenreader would present this, example only
"Form entry. Input name. Input email. Ignore this field it's for spambots. Input url. Submit" -- In this case does the message more naturally apply to email or url? I'd imagine there'd be a pause after input email (to wait for the input)? I need to set up a screen reader :)
Admittedly, I am not familiar with screen reader standards, but my gut feeling is that they are doing their users a disservice if they are not representing what browser users are seeing as similarly as possible.
Do you anticipate any problems with form auto-filling tools?
Depending on where it is the name= would be surname (where the form submission has a name field rather than a first name surname split), website, url, etc