When I was a TA in grad school, I did. We had no policy on late penalties so I accepted them for full points because I didn't give a shit about deducting points. You did the work so I'll give you points for it. However, I imagine it'd be very different if I ran an actual classroom as a real teacher or professor. Being a graduate TA is different because teaching is not meant to be a priority in the type of grad program I was in, it's just a service you perform for the university to get your tuition paid.