score:6
This practice is very common in Mexico car rentals. A renter can legally rent the car with only liability insurance (i.e., coverage for damage done to other persons and their property), but almost all rental companies (even the big names) behave as the OP fears: the customer is given the hard sell to buy more insurance, which puts the total price considerably higher.
Demanding and taking only lower limits, however, puts one at both civil and criminal risk if there's a collision. Mexico can (and does) actually take the driver from the accident scene to jail if no sufficient insurance is demonstrated. If higher insurance coverage is declined, the bill will be higher on the online quote, but less than one might pay in other locations. As an off-the-cuff estimate: a rental that quotes online at $10/day might end up costing $20. This is an increase over the online quote, but not a lot.
A very few rental companies take a higher road, and do not engage in this practice. We have patronized Cactus Car Rental in Cabo for years: their prices include a higher level of insurance, with coverage for damage to the rental car.
We've rented from both kinds of merchants. For us, the greater ease of no hard sell and more complete coverage is worth the higher price. Cactus' rates are higher than the low-ball quotes given by others, but in our experience reasonable. Their no up-sell approach is refreshing, straightforward, and quicker.
Source: I'm a lawyer, and we've rented cars from many sources in Mexico (mainland and Baja Sur) for decades.
Upvote:3
In the end I wasn't required to pay anything extra when renting with Avis, but voluntarily chose to take the liability insurance for $15/day. Your credit card would be charged with the following deposit:
Therefore I can confirm that Avis in Cabo doesn't have any hidden fees. Here's a copy of my final receipt: