Well... I've got a good 7 sessions (~7 hrs) with just the front strap mounted and no major mishaps. Before reading the posts since my last one, though, I went out and took off my strap. There's wind in the forecast for tomorrow, so maybe I'll get to try it. 99% of my experience to this point is on twin tips. I did try an old F1 surf-style board without straps once last fall in anticipation while waiting for my foilboard. Though underpowered, I was able to get up and go a little strapless, so I guess I have a little confidence. I am certain positioning and maneuvering the foilboard will be very hard.
One of the reasons I got this board was to see about the boundary conditions or limits. I have foil kites and I wanted to test the light wind end and also the upwind. I have always been able to do much better upwind than other riders on inflatables. Interestingly, in learning to foilboard, I have put my kites in the water many times this spring. Usually, it is rare for me to do that. The relaunch turns out to be quite effective. So far I am 100% successful (19/19 relaunches). I'm not going to count the one time the foil went and ran over the lines (!)