Amazon is being sued over labor practices - specifically whether or not physical "strip searches" and waiting for them should be on the clock or off.
Since this is going in front of SCOTUS on Oct. 8, we will soon know how this will play out.
Insofar as my read of the case is of interest, I think the plaintiffs will prevail - and I'm no labor unionist - this will be counted as on the clock time.
Simply because this step (the search to ensure that no shelf items "walk "out the door) is not an option; every employee has to comply, or lose their job. In contrast to other requirements (i.e. drug tests), this is a daily and fairly significant (per the article, about 15 minutes on average or 5% of an employee's work day) intrusion on what would otherwise be personal time.
As a back of the envelope calculation, we estimate Amazon to have to pay each warehouse employee an extra $5 per shift, fully costed. Compliance is rarely free, and in this case we think Amazon has to pay for it - which in turn presumably means that their pricing and other rates will go up a little to pass this on.