With care you shouldn't tip over
I always sail using the techniques of keeping the mainsheet in my hand (the camcleat holds the tension) this way it can easily be released spilling the wind in a puff. I also have a set of reefpoints in the mainsail (best $67 I ever spent!) and use them often. However, I disagree that the Day Sailer will not sail without the jib! Perhaps if the mast is leaning too far aft, but I find that like all small O'Days, the DS sails GREAT without the jib, and this is my "first reef", if the wind is still too much I reef the mainsail. I have owned my DS II for 6 years, previously owned a 12' O'Day Widgeon, I have never come close to capsizing either boat. Water has flooded over the side a few times every season, but by releasing the mainsheet the boat comes right back up. I sail singlehanded on Buzzards Bay, in Massachusetts. The afternoon seabreeze is usually 10-15 knots, sometimes higher. I have found that using a tiller extension allows me to sit on the side deck and this helps to keep the boat upright. A Day Sailer can capsize, especially while racing, however...they do not have to capsize. Someone said that capsizing is less likely on a lake than the "ocean", but what I hear about lake sailing suggests that the opposite is true. On the Bay the wind is fairly constant, lake winds seem to come and go (sometimes with gusto!). So, my plan has always been to be prepared for going over.....but doing everything possible to NOT go over! So far it has worked.