Random people hate being watched, or at least they hate knowing they are being watched by another person.
That being said, like someone else mentioned, Glass and AR-type products are very successful as productivity boosters in people who assemble products. We use Pupil Labs' glasses at our business to do gaze tracking. There's a lot of good use cases for this technology, but it's not cheap and it's pretty specific at this time.
It's not entirely clear what you're saying here. Does your business use these solutions as a way to enrich the information needed used by someone assembling your products, or do you use them to ensure everyone's eyes are looking in the correct direction while on the assembly line?
That being said, like someone else mentioned, Glass and AR-type products are very successful as productivity boosters in people who assemble products. We use Pupil Labs' glasses at our business to do gaze tracking. There's a lot of good use cases for this technology, but it's not cheap and it's pretty specific at this time.