It’s a lot more difficult to check with the date based pricing. They could raise some dates and not others. I think it might show up more easily with the flexible date tickets, as those seem to have more standardized pricing. Has anyone checked those lately?
I think they would prefer not to give notice if possible. Just make sure you are familiar with third parties who may have inventory at the old rate, and if you are an AAA member, check there. I was able to renew my AP through AAA at the prior rate after the no-notice increase earlier this year, even though it was a few months before I could renew with Disney.