Pay Taxes on Service Won but not Used?

What if you win a service but you don't use it. Are you still liable
for the taxes?

Here are examples of what I'm talking about:
A gift certificate to a local day spa. You hate spas and throw away
the certificate.
10,000 free minutes on a cell phone plan to which you don't subscribe.
One year of cable TV service, but you already have satellite and never
call the cable company to subscribe.

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