Oh my goodness, eavesdropping is listening in on a private conversation. If three people are standing in a loose circle and two of them are in casual conversation loudly enough for all to hear and while facing the third, that third person is welcome to join. It's implied by open body positioning, volume, and subject matter. If two people are whispering with their heads together, obviously the associate should stay out of that
I feel better about failing them if I am sure they were aware of my presence and still ignored me. If you would rather just stand there or silently examine produce? Do that. I wasn't saying you have to make sure they are aware of you, only sharing that I feel better if I give them as much room to succeed as I can.
Bottom line is being supportive of the client's objectives means checking for what they want to happen whether you want the same or not. If it makes you too uncomfortable to do that, the job is not a good fit.
It seems obvious to me that they want the produce associate looking around while they work, checking for people who need help. They want them engaging in casual conversation with customers who show openness to that. The examples are meant to convey depth of interaction, it's not a script.