That's a recipe for failure.
It won't be the money fairy visiting these restaurants, it will be their banks with foreclosure notices.
The restaurants that succeed are going to be those that can entice customers to come back. Surcharges aren't exactly enticements.
They have no choice but to raise prices when 1/2 or more of their tables are empty and they have costs over what they had before. The restaurant business is not very profitable so they don’t have fat they can cut. What would you prefer? Raise prices which will stay raised. Add a surcharge which they will drop when things are back to normal.