We implemented an aggressive onsite notification to make sure that users who have two copyright strikes are aware of all the details and have the information they need to make sure their account is not disabled under our legally mandated Repeat Infringer Policy.
Some of the feedback we received from users lately has focused on the fact that they were completely unaware of the strikes that they had accrued over the years, so they were taken by surprise when a third strike came in for one of their videos and Vimeo was forced to disable their account. The last thing we want is for users to be caught unaware and we believe that an unexpected account closure in the future is much worse than an (admittedly) harsh notification that you have two strikes now.
There are a few things to keep in mind: this warning is new but the strikes are not necessarily recent. This warning is to make you aware of pre-existing strikes. They may have accrued at any time over the life of your Vimeo account.
The best way to make sure that your account is not disabled for a third strike is to make sure that no further claims of copyright infringement are filed. As long as Vimeo does not receive any more takedown notices for the material you have uploaded, your account should be safe.