I also invested a bit into Rialto for the same reasons. I don't see many good reasons why someone would move a large quantity of tokens to an exchange if they don't plan to sell. It's possible they could be using it as collateral for short positions or loaning it out on Poloniex, but a sale seems far more likely. I'm going to write a script to monitor such moves and their results in the coming months. I'll make a post with my findings.