Etiquette for requesting an API key from a company

I need to request a number of API keys to pull up travel schedules and am wondering if there is a certain etiquette for requesting this information. Are there draft letters that exist? Has anyone done this before? I am referring specifically to companies that do not advertise public APIs or opportunities for website partnerships. I also know that many companies do not even offer these yet.

For instance, if I wanted to get access to the travel schedules and fares of the Green Ride Shuttle company in Colorado/Wyoming and connect this information in real time to my website, would I then need to contact the web admin for this company and ask permission via email?

I am completely new to this whole concept and was hoping someone who has tried this before might be able to offer some insight.