How do you enforce handwriting standards for homework assignments as a TA? I am a TA who is helping to grade student homework assignments for an undergrad engineering course which involves a lot of mathematics. The homeworks all together count for miserly 5% and is only graded based on completeness. One of my biggest petpeeves is poor hand writing for written work. I don't exactly have good hand writing, but for things that are turned in or show other people (i.e. for communication purposes), I always ensure that the quality of work is top notch quality.  

However, most students in my class have terrible handwriting to the point I cannot even decipher what they are trying to communicate. Wherever there is supposed to be a straight line, I see a curve, not even a well drawn curve. If students run out of space on their piece of paper, many resorts to cramming massive amount of calculation in the margins rather than starting a new page or even flipping the sheet over to the other side. Even worse is that most students write in pen, and when there seems to be an error, they have no qualm of scratching it out using a scribble. I am not a pen person so this is something I have difficulty in understanding. Homeworks are rarely stapled. Let's not even talk about the diagrams, I have no idea why they even bother drawing one. Most people just don't seem to care.



(a picture I found online just to give you an idea what it looks like, sometimes the entire page is crossed out because of some mistakes in the calculation)

I have been telling them to write neatly since homework 1. Yet this problem persists. The main problem is that the homework grades counts for so little, and there is nothing to enforce quality of homework. If a homework is completely done, even if the hand writing is so poor that I could not decipher exactly who handed in the assignment, I am still required to give full grade. I have talked to the professor who is running the course, and he basically gave me a "I don't want students whining over grades" sort of reply. I am powerless to change the policies of the course, and at maximum all I can do now is giving out recommendations to the students on expected, but not enforced, handwriting standards.

Is there anything I can do in my situation? I had hoped I could see a reflection of myself in this pool of students but I have yet to see that person which makes me a bit disappointed to be honest. Whether if these people go directly into the workforce, or remain in academia, clarity in communicating is very important and I fear if they do not change their habits quickly it could lead to some very negative consequences in their professional life. 

Am I overreacting? 

Should I tell them a white lie that I am going to give zeroes for unclear, poorly written homework but in actuality I will still give full grade for completeness?
My approach is simple- homework is submitted as a typed .pdf file, no exceptions.  Homework is submitted online through the course management system (Instructure's Canvas in our case), which enforces the required file extension.  

Yes, this means that my students need to learn how to produce typed mathematical equations.  They're welcome to use LaTeX (probably the best choice in the long term), Google Docs (which has a pretty intuitive system for math formulas that's adequate for most purposes), MS Word (which has an awfully complicated and hard to use equation editor), Apple Pages, or whatever software they like, but they have to convert the output to pdf so that I don't have to deal with all of these different word processing software packages.