The problem with the SCD type receptacles used in RVs and mobile homes isn't so much the recept. itself, it's improper punching down of the wires into the "stabs". There is a proper tool specifically for these but I've found at least of couple of SCD recepts. with wires only pushed down onto one of the two "stabs" as in the photo. One stab was bent to the side. They definitely didn't use the proper tool. No excuse for this.
Connecting to only one of the stabs means you will be doubling the amount of current going through a stab connection. SCDs go through very rigorous testing process to meet UL requirements and *should* not be an issue IF properly installed.
The bigger problem is that electrical in RVs never gets inspected by an AHJ for code compliance or workmanship.
SCD recepts are used in part because they are much shallower than an outlet box and thus fit into the thin walls RVs have. Recepts. in houses can also be back-wired where you can push in a stripped wire through a small hole which has spring loaded contacts inside. These can problematic sometimes. I'd take a properly installed SCD recept. any day over doing over a back-wired recept..
