Emergency pricing

If a person calls a plumber on the weekend or the middle of the night, they are generally charged a higher rate than for daytime plumbing. This encourages people to do whatever they can to allow the plumber to work during normal business hours. It compensates plumbers for unexpected loss of their time with family. It's a hardship on people who have truly unforeseen emergencies, though.

If a tree company cancels all of their scheduled work for two weeks and has its crew work long hours and weekends removing trees from houses: is charging three times their normal rate reasonable compensation? My neighbor and coworkers were rather shocked at the quotes we got for tree removal; accusations of gouging were made. A lot of people removed trees themselves or found non-professionals to do the work; this took a lot of the burden off the tree companies and the storm damage through the city was cleaned up faster.

I can see where it is unseemly to make money off of the hardships of others. But when a person needs an emergency service, providers of that service are not obligated to donate their time and expertise charitably. It's a fine line between reasonable emergency rates and gouging.