hazy summer weather, is often IMC in all but name. They don't tell you that when you get your PPL One needs instrument training to fly usefully, even if one is technically 100% VFR.
I am trying to figure out if that is really true, or if it is an old wives' tale, hence canvassing opinions and looking for evidence of accidents caused by it.
I did Dover-Calais once in very poor vis, but was down low enough to see the water and had no probs at all. I thought at the time I would have been OK a bit higher too.