Full-on grope, because nothing has been 'resolved' (or not) by the scan - but if you're opting out, you're going to get some version of a 'full-on' grope anyway. Same goes for ETD testing - opt-out, you may or may not get the ETD testing (at least in my experience).

It avoids a possible punitive wait for a dedicated groper that you experience at some airports. There's always a groper stationed at the exit of the NoS to immediately resolve any anomalies (or else the line starts backing up). Depending on checkpoint configuration, it can be easier to track your belongings and you're less likely to encounter a TSO who deliberately steps in your line of sight when you say you can't see your belongings from where you are waiting.