In article ZeUHf.772610$_o.182746@attbi_s71, Odysseus wrote:

I was checking the Travelocity web site for prices on Celebrity
cruises in April. I will be traveling solo.

On the April 16 cruise on the Millennium Celebrity offers a category Y
ocenview guaranteed rate of $900 per person double occupancy.
For a single, the lowest price for an oceanview cabin is a category 08
at $2261.

I am prepared to pay a single supplement but this is a single penalty.
What would happen if I booked two people at the $900 guaranteed rate
and one does not show up? I would not buy insurance so there would
not be a case of insurance fraud.

I did just that, not intentionally though. No penalty beyond paying for
the second person.