Suppose I create a new e-mail account, and use it to apply for another account on Stack Exchange (for this example, let's assume under the same display name), if a moderator determines that the owner was in fact the owner of an account that was suspended and deleted, can they apply the same suspension to the new account? Or is it new e-mail = new user/account?
If this is detected, they will usually not apply the same suspension; instead, they will apply an increased suspension. The user is deliberately trying to circumvent the rules, so the suspension will typically be extended from 7 to 30 and from 30 to 365 days (but this is, as always, at the moderators' discretion).