locking a rear brake on a curve usually results in a highside, so I'd say your wife was lucky.
5,000 miles over four years isn't much riding. If she decides to get back on, and hopefully she'll do more riding to keep her skills sharp.
Rocker59 (aka guzzimike), Aux Arcs
Moto Guzzi Sport 1100
"Do what you can, with what you have, where you are." - Theodore Roosevelt