The sentence in the title of this question is shown on hovering hidden accounts when one visits the page http://stackexchange.com/users/userid/username?tab=accounts. I have given a screenshot below.
(I have hidden some of my accounts from the screenshot too!)
The tooltip currently shown is
This account is hidden and will is only shown to you and moderators
As far as I understand, the sentence is wrong due the word "will" shown in bold!
Here are a couple alternative sentences that could be used:
This account is hidden and is only shown to you and moderators
This account is hidden and will only be shown to you and moderators
I like the first one – all in present tense. But Jon Ericson says future tense in the second one implies promise. I say to this, present tense in the first one implies promise implemented :)
I don't know, it is up to wise moderators to decide. I just did my part.