You could make a withdraw large enough and wait for it to be processed from the cold wallet if you really cared. Otherwise, I doubt you'll get any form of verification.
It does not attract me to make a larger deposit to the bitdice scam.
How do you conclude that the address
35d3dD1hMjrgxG3x23zTS8Rvjsbk7sxaGv belongs to bitdice.me?
I traced it from one of my larger withdraws from a while ago. You could probably use a service like Chainalysis to learn about BitDice's hot/cold wallets if you wanted to instead of taking my word or testing it yourself.