I have heard from the excavator community over the years. They often point out the utilities seem to not care, and don't show up to mark their utilities on-time. The famous telco appointment time of between 8 and 5, if at all. The excavator is losing money for every minute the locate marker is late, or doesn't show up at all. This isn't a lot of profit margin in excavation. Sometimes the choice is between not digging and definitely going out of business, or digging and possibly going out of business.
Why is the contractor waiting around? I'm not very familiar with how things are done in the construction industry, but I see a lot of paint on roads and sidewalks around here. I've seen occasional people out putting down paint without any contractors waiting around. I thought the standard practice was to mark the limits of the area you want to dig in with "USA" (Underground Service Alert) and then call the USA 800 number a few days before you want to dig there. That gives the USA people time to contact all the utilities so they can come out and mark the area. I should read the fine print on a call-before-you-dig sign the next time I get a chance.
As far as sending a big bill to the contractor. As has been pointed out before, most excavators have the minimum insurance and few assets. And the cynic may look at the number of contractors hired by utilities
Does it work to sue the organization that hired the contractor? If not, why?