Yes we know salt and water arent dangerous. We ask that you wear labcoats etc. in the lab despite not working with anything dangerous so that you form a habit of using protective lab garb regardless. Because a lot of accidents in the lab cause harm because someone thought it was safe to lower their gaurd and it wasn't.

Case in point: one of my undergrad professors during his time at grad school walked around in the lab without his safety goggles on. He felt comfortable doing that because he wasn't himself working on anything particularly dangerous at the time. He was just walking from one end of the lab to the other. Well it turns out that someone else was. There was a fairly good sized glass bottle with fuming nitric acid and other stuff for a reaction in it that was boiling away in the fume hood. No I dont know why the sash was as high as it was. There was a funnel sitting in the neck. Occasionally the jug would "bump" in other words, some liquid would spurt up top due to a slight build up in pressure caused by intermittant boiling. And one time while he was walking by, it burped a lot more violently than it normally would and some of it sprayed into his eyes while he was walking by. He spent the next two weeks in a dark room occasionally dropping antibiotic eye drops into his eyes so his corneas would heal. Apparently it was fairly painful and every blink felt like he rubbed sandpaper over his eyes. If it had been a strongly basic solution, it would have eaten his corneas and potentially blinded him permanently. Point is, we are trying to stop you guys from becoming too casual in the lab so you dont have your corneas half eaten by nitric acid because you felt safer than you actually were.