Ask HN: Online Reservation scams: what’s the worst you’ve seen?

We did a road trip around Washington and ran into a number of reservation scams. Online hotel booking specified $47/ night in “taxes and recovery fees” – actual taxes per night were only $11. Online hotel reservation charged $15 / night for parking – but upon arrival we discovered parking was free and un-ticketed . $15 charge for nothing. USFS campsites offer 50% discount for America The Beautiful pass holders when paying in person, but reservations.gov does not honor the discount. Also reservations.gov charges a 10% booking fee. A $13 campsite in person costs $30 /night booked online. When visiting a popular tourist town, public parking was $6 / day. Using the recommended app to book daily parking rates were charging $20 — a > 300% increase. In the end we booked in person to avoid the scam. We saved over 50% on the hotel and 75% on daily parking. This was just a single 5 day trip. What other online booking scams have you encountered? How do you get around them?