@Douglas353 There are scammers everywhere. The US doesn't have a corner on that market, and that scam you experienced is a known online scam not dependent on area- they are sent to hosts worldwide. That one you just got is not necessarily from a US person- it could as easily be sent from South Africa or Russia or Chile.
You were advised to report the scammer- where did I suggest you should just say no? Sending an outrageous special offer doesn't help other hosts or stop the scammer- only reporting them does, as Airbnb will shut down the account. But the scammers just open new ones- they can be slowed down, but not totally stopped. Cybercrime is a modern-day online issue, not something limited to Airbnb.
The difference between inquiries and requests is, for starters, clear on the message title. It either says Inquiry or Request.
Inquiry- a way for guests to ask questions without committing to a booking. Because even if you pre-approve, the guest has to take another step to actually book.
Inquiry choices- Pre-approve, Decline, or just answer.
The reason you are being advised to just answer (No, Go away scammer, I wasn't born yesterday) and report, is because answering fulfills your response requirement, while declining hurts your acceptance rate, something you have already experienced.
Requests- options are Accept or Decline. You can message with guests before doing that, but it doesn't count as a response- to fulfill the response requirement, you must either accept or decline within 24 hours, unless the guest withdraws the request before then.
When you accept a request, the guest does nothing further to book- Airbnb immediately charges them for the booking.
Clear?