I think this is just a nudge to capitalize on a good season by getting new folks thinking about season tickets. I don't think it's directed at current season ticket holders.
They did this at least once before, I think in the summer of last year. I was thinking about buying basketball season tickets for the first time and saw some communications about a $50 deposit. I called the Bulldog Club/ticket office to ask what effect the $50 deposit had. After a bit of throat clearing, they admitted there was no benefit to me. I'd still have the chance to buy tickets and select seats based on Bulldog Club rank. Paying the deposit did nothing for me and not paying it had no negative impact. I didn't pay the deposit and later got season tickets that I was happy with.
I plan to ignore the current deposit suggestion and will just renew my tickets when the time comes (presumably this summer).