So I picked up a J5-V2 Tactical Flashlight as a possible bike headlight, on the basis of a 750 (“max output”) lumen LED, zoomable beam, and use of standard 18650 lithium cells (rather than USB charging). The geometry required to stick it on the Tour Easy remains a puzzle, but an az-el dingus replacing an upper fairing mount may work well enough.
Anyhow, it seems the LED in this flashlight fell on the floor during assembly, where the (silicone?) LED emitter lens picked up a remarkable amount of dirt:
The inside of the front focusing lens carries an array of scratches or, perhaps, a greasy fingerprint that serves the same purpose:
All vendors tell you to contact them before posting a critical review, although they often don’t provide much in the way of contact information. I sent a note with photos to J5 through their website’s contact info; having not heard anything after three days, I’ll fire up the Amazon return process …
The Smell of Molten Projects in the Morning 
I purchase my fair share through Amazon and usually quite satisfied. Aside from the increasing frequency of poor packing, the items usual arrive in undamaged condition. One thing I have noticed on returns though is that there have been a few lately that require return postage to be paid. Sometimes this is refunded other times not. I think return postage is automatically paid if it is sold by Amazon vs just using Amazon as a store front. I’ll also note that I do not return many items, but just passing this information on so others are aware of it.
That’s an absolutely crucial difference: in general, if it’s “sold by X and fulfilled by Amazon”, then I’ll buy directly from X on eBay. If X doesn’t exist anywhere else and I want that specific thing, then I’m stuck with Amazon, which doesn’t happen all that often.
I rarely use Amazon since they won’t ship most items to my country and you have to jump through hoops to find out if they will, how much it will cost and where the item is shipping from (important for customs fees). Mostly I use eBay which does that part much better, and I’ve been merciless with several sellers in case of faulty or wrongly described items – so far to the effect of full refund or replacement item being sent after only one or two emails an no extra cost.
I was once asked to return the faulty item to China, but upon explaining that shipping exceeds the value of item they sent a replacement without to many harsh words… I think I didn’t even have to use the term “negative feedback” :)
As nearly as I can tell, anything less than five stars in all categories counts as the nuclear option. Plenty of the low-end sellers seem to exist only to farm high reviews and I haven’t been able to follow the money in that operation.