That probably has more to do with the boat stirring up the bottom. Iv caught a fair few fish moments after a boat has gone over the top of my baitApparently a lot of the brightness claims about Chinese made headlamps on Ebay are false. Some of them have unsafe charging units as well. Got this from a sea fishing forum a few years ago.
I have a Fenix HL60R. Lots of brightness options, waterproof, shockproof, rechargeable and a 5 year warranty. Had mine for 3 years and I rate it very highly. Only use it when I have to and on a low level. I turn it up to net a fish and it seems to spook them a bit. However, last season a huge boat went up the river (Trent) with an extremely bright light (on a really dark night). It passed over my bait and I thought it would ruin the fishing. 5 minutes later I had a bite from a pb 13lb barbel!
Castor definitely gets alot of bright lights Ray!!!!!!I have had the same thing on the nene just lately and although I do have a very bright headlight I would never shine it on the water on into another anglers swim but I do have an energiser headlight with a red led for baiting in but as I am older my eyesight is not what it was and to do some things I need a bright light and can't do without it sometimes