Exactly what type of proof are you looking for? I understand your point, but there is very little to "prove" you were at one of these places...
I suppose someone could scan a letter they sent home, or a sheet of paper that has SCL on the top etc... But it isn't always easy to come into contact with this stuff... On my site, I do have pictures of myself at Tranquility Bay, which I do feel adds a bit of validity, but that's all I got... And I would never have had those if I hadn't turned 18 while there and requested to leave (thereby getting my mother to come down to try and convince me to stay, which obviously didn't work... but she did take pictures lol)...
As for your original question:
I attended SCL for a short time after I was at Tranquility Bay... The fact that I went after TB is important because I was already used to the most severe facility in the WWASPS umbrella... That said, I was relieved to be at SCL and out of TB... I didn't experience any physical abuse at SCL (other than a couple fights with other kids there... which actually occurred quite often when I was there)... But I will attest to the same ridiculous and harmful "regime" that they run throughout WWASPS' facilities...
We did have hot showers and washing machines. We also had food that we were somewhat used to. But we did not have; proper education, medical care, properly trained staff, communication with our real families, or any privacy ever (As was most apparent with the "man child" who slept above me and rocked the bunk every night doing what a lot of people do... hint hint)
I did see the "hobbit", and saw kids get stuck in there... Although at TB they would stick you in OP for months at a time, SCL seemed a bit better and might only put you in the hobbit for a few days at a time (still cruel and not healthy for a developing person)... And when the kids weren't in the hobbit, I saw them digging ditches or breaking rocks up... SCL also uses the seminars (as all wwasps related facilities do), which in my opinion are brainwashing clinics with close ties to cultish behavior.
And most importantly, SCL is under the umbrella of WWASPS. WWASPS has had all but 1 of their overseas facilities shutdown amidst allegations and findings of abuse... This should be one huge red flag...