You are right RNP should be cheked. I try to do the following.
Before RNAV we used to check or nav aids for the approach. Well with RNAV you do the same.
If you use RNAV for arrival or app just check it as you used to do before with the conventional means. With computer technology introduced in navigation we are forced in a more monitoring function and that exactly what we should do.
Before RNAV .....app checklist....nav aid identified
With RNAV .......app checklist.....nav aids...that is in this case RNAV....checked and valid.
Greetings
Curly Mountains