I just bought a 2018 Certified RDX Tech package and love it. Don’t like not having apple car play but love everything else. Don’t miss the collision mitigation stuff- I’ve driven cars with it and it was more annoying than helpful.You do have the option to turn off some of the AcuraWatch features at anytime. I like the new features and leave them on. I get the occasional flash from the CMBS auto braking; but, never had it do a full panic stop from nowhere. I would let her test drive both versions of the RDX w/ and w/o Acurawatch to see if she will like the added safety tech (my wife loves having AcuraWatch).
The used vehicle market is red hot with higher than normal prices right now. I would test drive the tech level/year you want to see if you/she really likes it. I would even compare prices in a 1/2 to 1 day drive to see if other dealerships might give you a better deal. My local dealership was playing hardball until I showed them a cheaper price at another dealership for the same exact MDX and they price matched on the spot. A CPO RDX does a 182 point inspection and increases the 4/50k basic warranty to 6/100,000 miles and the powertrain goes from 6/70k to 7/100,000 miles.
Another minor "con" with Acurawatch is going with OEM glass if you need a new windshield. Getting OEM windshield glass and the Acurawatch camera needs to be calibrated afterwards is the best way to get the system up 100%. Some folks had issue with aftermarket glass. I would check on your car insurance for glass replacement coverage because it can cost +$1000 for OEM glass+calibration. Some had some issues with extreme heat and effecting the camera above the rear view mirror (overheated camera message). I live in the southwest with +100 degree F days 1/4 of the time during the summer and never had that issue. Other than that, zero maintenance or issues for any other AcuraWatch system.