We did it last year. I was at Taco Tech game which was 80's and sunny and everyone did a decent job with the masks. That was when it was still in doubt if fans would be allowed at future games if they didn't wear the masks though. If there is no threat of loss or personal punitive action, I am sure more will ignore the recommendation to wear a mask. Just human nature, if the reaction will have no personal impact on you, you are less likely to pay attention to it, thus if you only go to 1-2 games per year and not wearing threatens reduced capacity, I am sure many people won't care and not wear.
I have always approached it as a time of exposure thing. If you are stationary and near people, wear a mask. If you are moving and not in vicinity of any one particular person for more than a few seconds, the risk is extremely low, especially outdoors.