It is from this video. It is at 6 minute and 12 second. Here is the context:
Dosage is incredibly important. I guess cancer patients would know that dosage is important because when you are getting irradiated in order to target something like tumour, you are not getting enough radiation to be harmful to your entire body.
I am confused because there are no any conditional sentences, but would was still used. Does the speaker mean the paients probably know or that they probably will know that...?