Only people who signed up for certain variable rate plans with retail providers such as Griddy, which is uncommon. They gambled that there wouldn’t be enough of a shortage to cause the wholesale price to spike and they lost that bet. Or more likely, they didn’t fully understand what they were signing up for. Most people pay fixed rates for power.
We should talk about how these customers will get bailed out. Who do you think should pay? The retail utility who they had a contract with? I do not see a legal basis if it was a valid contract. Besides it is these companies who have the large bill they have to pay. The state? That's like a big GoFundMe paid for by all those who pay state taxes.
If the generators do not get paid for making power when it was really needed, they will have little incentive to make power during the next shortfall. That could get really ugly.