There is a section in the Winner Selection Policy, Winner Selection and Reported Domain Policy, that states, "If a creative reports a domain, the CH does not respond to the report, and the contest is abandoned; this creative will be added to the random winner selection process." Therefore, a contest with only one top rating could be split per this policy.
However, going forward, we will only consider the reported domains if there are more than the minimum number of creatives who qualify to split an award. For example, in case of $100 award, we will only consider reported domain if there are at least 2 creatives who are eligible to receive the split award.
We have updated the policy: http://helpdesk.squadhelp.com/important-sh-policies/winner-selection-policy