Sallye, I'm not sure you ever got an answer to your question about hydraulic trailer braking systems. I'm not an expert, but I can give you the basics. Built within the trailer hitch, there is a hydraulic master cylinder. Then there are hydraulic fluid lines to the brakes
where there are slave cylinders. When towing, the trailer behind you has motion inertia. If you step on the brakes
to slow the tow vehicle, the faster motion of the trailer essentially tries to push the tow vehicle a bit. This compresses the master hydraulic cylinder in the tongue, which forces hydraulic fluid to the slave cylinders which activates the brakes
. Once the trailer brakes slow the trailer down enough to match the speed of the tow vehicle without pushing, then a spring built into the tongue pushes the master cylinder back out - releasing the pressure off the hydraulic fluid, releasing the brakes. It's a pretty delicate balance, but essentially the trailer brakes itself anytime it starts to push against the tow vehicle. No need for brake controller in the tow vehicle, 7-pin receptacle, electrical
wires between the tow vehicle and the trailer, etc. It generally works great unless: 1) you are constantly and drastically changing the weight
carried on or in the trailer, or 2) you have long, steep downhill grades where the trailer is constantly pushing the tow vehicle and there is no way to let up on the brakes to dissipate some of the heat being generated between the brake linings and the brake drum. I would imagine more expensive hydraulic trailer brake systems for "big boy" trailers have fixes for both of the above, but I doubt if that's the case with the Lil' Snoozy system given the relatively light weight
of the camper. But that would be a good question to ask them. Note that without electric brakes, you also don't have a way to manually brake the trailer if trailer sway is a problem (probably not going to be a problem with a quality camper like Lil' Snoozy). I hope my explanation is somewhere near correct (if not, someone more knowledgeable please make corrections), and I hope it makes sense - mostly.