Yeah in most applications, 50w sq/ft would be complete overkill. Better have some heavy duty ventilation/CO2 supplementation. Or they would be doomed. Especially in a tent.
I think tents can be a good idea, but I also think they are a recipe for having a hard time to get enough fresh air exchange, to use extremely high amounts of light. Im growing in a huge attic,40 x 35 x 7-10ft ceilings, depending on location in attic, and have 4 windows, and a roof ventilator. Plus a ox fan going 24/7.
Though, as if right now, Im only able to use about a 6 x 6 area, and 1 x 1000w Hortilux HPS for flowering. I vegged with a 1000w 6000k Halide.
Reason I use 40w sq/ft, is because when Gavita introduced their 1700e, it was billed as a direct replacement for a 1000w HID, in a 4 x 4 area. This was straight from them. Actually it comes out to 40.31w sq/ft.
The 1700e, is 645w. So of course I just divided 645w x 16 sq/ft, and come up with 40.3w-sq/ft. I know LED have got a BIT more efficient, but, not that much. Might be down to 38w sq/ft, with the very best of them. A 645w Gavita 1700e is 1700umol, and a 1000w Hortilux HPS, is 1650umol. So, thats how I determine what I would use, as I mainly use HID, and if I want to use an LED, I want it to have the same amount of light sq/ft, ad an HID. And its said, LED is about 1/3 more efficient. 1/3 of 1000w is 666 2/3w.
So instead of going by what people say, I just go with what Gavita has done the research on. And for sure less w sq/ft will still grow weed. I also believe one should take fresh air exchange, as a main priority vs how intense of a light to use.