I've seen that Toyota one before. I hate people that "honk" their arrival and are too lazy to get out of the car... so they got what they deserved in my book. That just irritates the hell out of me, especially when they sit there and keep doing it.
I used to be a driving instructor in a different lifetime. Parking practice always took place in a BIG OPEN parking lot, away from any possible obstacles. Once you know their skill level and confidence (or lack of) you can assess whether to move on to trickier stuff. It probably also goes without saying, but a husband teaching a wife (or vice versa, or any other combination of family members) is usually stressful and causes people to make mistakes.
The washer fluid is NOT fine!