How are they going to get feedback? Are they just going to monitor social media or something? There's no "trial feedback" number or email as far as I'm aware, so at best it's going to be service centres that get the flak from irate customers (Tesla and non-Tesla).
Normally a trial has some kind of parameters that are measured, but it's really hard to see how this can be the case with the sites they've opened, unless Tesla are going to deploy a member of staff to sit there and watch what happens? They might get a sense of demand, but the other variables like bays being blocked, etc is going to be oblivious to them unless the feedback gets back to them somehow.
It all seems pretty shambolic.