A Kansas City traveler booked Avis's cheaper "mystery vehicle" option and got charged an unexpected upgrade fee after returning the car—despite never requesting it. The company claims 9/10 times these charges are upheld, raising questions about how many business travelers miss these fees.
Rental car "mystery vehicle" deals promise lower prices in exchange for not knowing your exact car model until arrival. But a r/TravelHacks post reveals how this pricing model may expose travelers to unauthorized upgrade charges.
The traveler booked a mystery vehicle for a Kansas City trip specifically because it cost less. At the counter, the agent asked: "Are you okay having an EV?" The traveler said yes, knowing electric vehicles were a possibility when booking the mystery option.
Upon returning the vehicle and entering the airport, an e-receipt arrived showing an additional upgrade charge. No car seat, no toll tag, no added insurance—just an "upgrade" from one vehicle class to another.
When the traveler called to dispute the charge, the Avis representative claimed they'd upgraded from one class to another at the counter. The traveler's response: "How is that possible? It was a mystery vehicle." The entire point of mystery bookings is that you don't select a specific class—you accept what's available at the discounted rate.
The Avis rep's explanation: the traveler was "probably confused at the counter." But according to the post, the counter interaction consisted of confirming insurance information and being asked about the EV option. No discussion of upgrades occurred.
The representative then stated that "9/10 this will be upheld." That statistic—whether accurate or intimidation tactic—raises alarming questions about how common these charges are and how many travelers don't notice or don't bother disputing.
The traveler noted a critical detail: they didn't know the make, model, or type of vehicle until reaching the parking spot after the agent handed them keys. This timeline makes it impossible for the traveler to have requested an upgrade at the counter—they had no information to base such a request on.
Disputing the charge through American Express business card protections should resolve this specific case. But the incident highlights a potentially systematic issue with rental car upgrade charges and mystery vehicle bookings.
The post's author asks an important question: Do rental desk agents get commission on upgrades? If so, this creates incentive to charge customers for "upgrades" they never requested, banking on travelers not noticing or not having time to dispute during business trips.
For business travelers especially, this practice could be widespread. Many companies reimburse car rentals without requiring detailed receipt review. A $20-50 upgrade charge might slip through expense reports unnoticed, multiplied across thousands of rentals.
Rental car companies have faced scrutiny for years over additional charges and upselling tactics. Documented issues include pressure to accept insurance coverage, fuel options that cost more than gas stations, and toll programs with high administrative fees. Unauthorized upgrade charges represent a new frontier in questionable practices.
The mystery vehicle pricing model itself isn't inherently problematic—travelers trade choice for savings. But if that trade-off becomes an opportunity for unauthorized charges, the supposed savings evaporate.
For travelers using mystery vehicle or similar discount rental options, the advice from this incident is clear:
1. Photograph or save your initial booking confirmation showing the mystery vehicle rate and terms.
2. Review the contract at the counter carefully before signing. If charges appear that weren't in your booking, question them.
3. Check your e-receipt immediately upon return, before leaving the airport. If unauthorized charges appear, return to the counter while you're still there.
4. Use credit cards with dispute protections rather than debit cards. Card companies can reverse charges while investigations proceed.
5. Document the counter interaction if possible. Note what was discussed and what wasn't.
As one commenter summarized: "I don't care if the charge was $5 more. I did not ask for it." The principle matters—especially when rental companies claim these charges are upheld 90% of the time, suggesting most travelers either don't notice or don't successfully dispute them.
