The thing is, following just the tow vehicle's tongue weight rating is not going to be enough. Tongue weight is concentrated at the tow ball, which sits probably 2-3" behind the rear bumper. This hitch hotel monstrosity is 35" long, which means the CG is at least 17" from its front edge, and potentially gets much worse when you load it with coolers and other junk. So worst case you could have those 350-ish lbs as far back as 18-20" behind the draw bar.
Some elementary math using the XV Crosstrek in their video as an example:
XV Crosstrek Curb Weight = 3200lbs.
Since it's a FWD-based car, let's assume only 45% of this is on the rear axle. Let's say you have an average-sized family of 4 in the vehicle. That's 500lbs. At 500+350 lbs you're already at the GVW of the poor Subaru with the cargo area (and most likely, the fuel tank) completely empty, but let's ignore that for a second.
Wheelbase = 2835mm
Overall Length = 4450mm
Rear overhang (approx) = 0.5* (4450-2835) = 807.5mm
Hitch hotel worst case CG = 20" = 508
Total distance from rear axle to load center(add 2" for drawbar) = 1317.5 mm
Actual load on rear axle = 350* [(2835+1317.5) / 2835] = 350*1.5 = 525lbs!! You decide whether a Class 2 hitch is strong enough at this point!
Further, the effect on the suspension and dynamics of the vehicle:
Typically 50% of front passenger weight is on the rear axle, and rear seat passengers are 90%. So that's an easy 310lbs on the rear axle.
Curb rear axle load = 1440 lbs (45% of total)
Passengers = 310lbs
Hitch hotel = 525lbs
Total rear axle load = 2275lbs
According to Subaru, rear GAWR = 2200lbs . OEMs don't joke with their GAWR numbers, it isn't a guideline, it's a hard-stop. Actually you can somewhat exceed GVW as long as you don't exceed the individual GAWRs (practically, not legally). When you exceed the axle ratings you start bending or breaking suspension parts in rough service, period.
In this example the vehicle isnt even physically full yet except for 4 warm bodies, and it's already close or over the rear GAWR.
People are free to bolt on whatever they want, but you can bet when I see this thing on the freeway, I'm going to make myself scarce from it's vicinity...