As a ex Verizon cable splicer I have probably driven in more bad nasty weather then the average bear. When moving along in very poor visiblity at maybe 20-30 mph I always had my flashers on and I appreciated others having them on also. The bright flash gives you maybe a 100 ft more of warning which on slick roads means a lot. There are times when I could not see the normal driving light but when it flashed I could see it. No, you don't mistake it for a parked car. If it is parked you will have plenty of time to react, you are not doing 60 mph remember. I high doubt you will ever find a hwy patrol that will pull you over for having flashers on, in fact I have followed Pa Hwy Patrol with their flashers on. Oh if it was illegal why do snow plows run with their flashers on all the time. If you can pull over, do so, but if you must press on then get your flashers on if you are only traveling 30 mph in poor visibility, some of us want to be able to see you and have time to react.