I'm going to say yes the tetra is contained and base it on the attached image. If a tetra leaning against the Alliance Station Wall is ok then a tetra leaning against the side Plexiglas should be ok since they are both field elements.
One thing I have noticed about the containment rule is that many robots drive into goal to get back in the home zone. Sometimes it looks like they might be touching a tetra, making it not contained. This can be very important in determining ownership of the home row. It is not easy to see this from the stands, so I would like refs to give a thumbs up, thumbs down signal to whether a questionable tetra is contained, like they did for hanging last year and "on ramp" the previous year. They can even bring back the calibrated piece of paper
