Many factors come into play.

As long as you acknowledge, and are aware, that the Cabin and Cabin Plus technically exceed domestic carrier restrictions, there is always a chance of gate check.

Otherwise, it is just a spin of the wheel on what gate agent you get for your flight.

Most of my flights have not had an issue, but the times that I am stopped by the gate agent, I don't argue, as I knew the Cabin exceeded the dimensions state by the carrier.