Believe me I know, I lost one these bad boys about 7yrs ago to jumping out. The Flame Wrasse I just got was hand picked by LFS so its the best of the bunch!
+1 for sure and they find even the smallest opening even some that may be just too small and then get stuck in it and can get back in the water ... Some are relentless as wanting out for no apparent reason most of the time ... they just like to jump ... Those tanks withe European type build with the horizontal ledges on the inside that they fall on and slide back in the tank may work as long as those ledges are wide enough ... but still a cover is IME better, as long as it does not shield the light too much if it is needed for what else is in the tank.