@Becky19 - I want to assuage your fears. If your personal ID is verified (which yours is) and you have Instant Book turned on (which you do) with the requirement the guest be fully verified before booking turned on (guessing you do have this requirement), the guest will not be able to complete a reservation without it. This is an automated process built into the software and despite what the second help center person told you, would not apply to the above conditions and would prevent the guest from booking with you. There is no "override" and Airbnb will not approve a guest on your behalf that does not meet your criteria. This violates their Terms of Service.
However, a guest may be able to book a "few times" before they have their profile verified as long as they are booking at locations that do not require a verified ID. Again, this is an automated process, no one is looking at each and every reservation unless there is a problem. The second call center person was only partially correct and definitely misleading.
In all fairness, you probably dodged a bullet with this guest because anyone who doesn't trust and become verified is, in my opinion, already a problem guest. What do they have to hide? A criminal background. Of the 4 or 5 my requesting guests who couldn't get verified or wouldn't, some online sleuthing resulted in mug shots each and every time. One guest it took 3 days because she had been arrested twice and they had to verify it was for DUI and not something more sinister. Chinese verifications take longer because they don't have Facebook or LinkedIn, but getting verified requires their passport.
In the future, these links may help to explain Verified ID to a guest and how it is used at Airbnb. When a guest is hedging, this information seems to soothe the anxiety.
https://www.airbnb.com/help/article/1237/how-does-providing-identification-on-airbnb-work
https://www.airbnb.com/help/article/4/how-does-airbnb-help-build-trust-between-hosts-and-guests
https://www.airbnb.com/terms/privacy_policy