Trust me the chances of being attacked are slim,and I have had them howl near me years ago before I started hunting them and it's enough to send a shiver down your spine.Of the 11 years that I have hunted coyotes,I have had only one growl at me and I was bow hunting when I saw him and called him into range and missed him with my first shot and started lip squeaking to stop him and he looked up at me as I was knocking another arrow in my bow and growled and barked,just before that magnus stinger sent him to doggie heaven,my only coyote with a recurve bow and the only one that ever showed any aggressive behavior,and I beleive that was because he didn't know what I was perched up in that tree.I have had them within ten feet of me on the ground when they rush the call and have never had them do anything but give me a very bad look before the loud boom.I have thought that they were going to run into me when they do their death spin after they have been lung shot .And yes to your question about the light.Any un-natural light will spook game of all sorts including deer especially a mature animal.I walk in,in the dark and leave the same way, so not to spook animals that I cant see.And if that coyote was a howling and a yipping and wouldn't shut up,that was an alarm howl they will do this sometimes if they see you,but most of the time if they see or smell you,you will never know it, they will just slip away undetected.Good hunting and dont let them bother you,the deer usually wont even leave a field when a coyote is in it,if he dont get to close to them.