Currently, we're using values from 0 to infinity in the URL parameters for pre-selecting a bucket. A value of "0" can lead to problems in mass mailing software, which converts 0 to an empty string.
Instead of numeric values in the URL, use alphabetic values. This is done in BucketSelectionServiceProvider because the rest of the code (and the cookie values) should stay the same.
Determine if we need to have backward compatibility to existing URLs.