Do I honestly need a doctor's note?

Recently I have been quite ill. Luckily, I have very understanding professors who want me to be healthy and succeed. This good will, however, does not excuse them from requiring something with which I morally disagree with: a doctor’s note.
We’ve flown the coop and no longer have mothers to write notes to our teachers, saying “My kid was throwing up, so I kept them home today.” In their stead, employers and professors require us to bring in notes from doctors to prove we’re sick.
Perhaps it’s my Kantian leanings – I can’t understand why someone would say they’re sick to get out of something, since lying is against the categorical imperative – but I’m not sure why people can’t believe us. When you say things like “I had a really high fever for two days because I had the flu,” or “I was throwing up all day, so I couldn’t come to class,” or “I have asthma and couldn’t breathe yesterday, so I stayed home and slept so it wouldn’t get worse,” it would be nice to be believed.

At King’s we talk a lot about self care insofar as it’s important to take care of our mental health. But why do we never talk about the physical side of things?
Most of the time when you’re sick with the flu or the cold, the best thing to do is stay home. There are many reasons for this. If you rest early, you won’t get more sick. By going out in public, you expose others to your illness and I’m 100 per cent not down with that.
But most of the time people don’t see this as an option because they “can’t miss any time,” or “don’t want to see a doctor,” and I believe that at least part of this is because of the doctor’s note.
As institutions seem unable to believe their employees or students are sick without documented proof, the wait times in emergency rooms – which I have spent a fair amount of time in this year – and walk in clinics becomes so long that they are almost unuseful, and a place where only the seriously ill feel they can go for treatment. Many doctors also charge for doctor’s notes now, in an attempt to dissuade people from getting them.
After I recovered from my most recent illness, I went to see my general practitioner. I discussed this issue with her because I thought it was important to have more than the ramblings of someone who is generally upset at almost everything.
She also dislikes this practice and was only willing to write me a note – which I failed to get while in emergency, because I was more focused on being able to breathe then on getting a note to excuse my absences – because I had made the appointment for another reason and I was really sick when I missed time. She also added that she doesn’t want to see people when they’re vomiting either, because she doesn’t want to risk catching what they have. Having someone who is sick like that in her waiting room is bad for her practice, and it probably would have been better for the patient to stay home and rest instead of coming in for a note.
To summarize, I understand why doctor notes are necessary, but I think the practice needs to be seriously rethought. When you’re ill, you’re not thinking about getting a note to excuse your absences, or at least you shouldn’t be; you should be focusing on getting better. When you have the flu and go and see a doctor for a note, you’re putting dozens of people at risk. Doctor’s notes put extra strain on our sick, our doctors and our medical facilities, and none of this benefits anyone except for the person who needed proof to believe you.