if it was that low they may have done serious damage and greatly reduced the life of that engine! 3.8 qts is about right.

Kill switch in the on position I hope you meant. The engine won't crank if it's off. On meaning run not kill.

I would be jumping up and down at the dealer and want either a new engine or complete rebuild done by someone else but paid for by them. If they don't know you rode it I wouldn't tell them and just say you checked the oil and it didn't have any!

I learned all I need to know about life by killing smart people and eating their brains.
Eat right ,Exercise ,Stay fit, Die Anyway!