If you were a teacher, would you turn a blind eye to your student cheating on an exam?

Depends. If I say no resources then no resources but if I don't specify... I don't really. care just don't make it super obvious. I would let that student slide if that happened bc that was probably nerve wracking for them hahaha but honestly resources are okay unless it's like a state test or a big exam/final. I feel especially this year i'm okay with it but as we take laptops away more and more and sort of go back to normal I think the rules will begin to apply again.

Yes, I would 100% turn a blind eye to cheating.

Just because the teacher didn't say anything at that time doesn't mean that it wasn't handled at a later time more privately.

Reacting right then would have been disruptive to the other students, and would also have provided an opportunity for them to cheat too, while the teacher's attention was distracted.

I would have kept that student back for a private chat at the end of the exam.

I didn't turn a blind eye to cheating but I never directly accused a student of cheating.  I used to write on the student's test that I found it interesting that the student and the other student had exactly the same answer and made exactly the same mistakes. Another technique I used was to Xerox the test of the cheater and when the tests were handed back I gave the student the Xeroxed copy and then made a big production that I returned the copy instead of the original.  In both cases I never had a student cheat again.  In subjects where laptops and other devices were allowed to be used by the student I gave no benefits of the doubt regarding their answers. 

Teachers don't turn a blind eye to cheating as they have their individual ways of dealing with it. 

The teacher possibly didn't hear it even though it was loud enough. I know people who if they are concentrating on something can't tune everything out (I can't). But more likely the teacher would address it later as it is better not to disrupt the entire class if a quiz is going on and better to have the discussion in private or the teacher simply doesn't care anymore because students and their parents have beaten down teachers when they address cheating. 

the teacher can, of course, mark the student's response wrong ... or even issue a zero on the whole exam for cheating

Not a chance in hell would I ever let cheating slide. She would be so busted.