When you sign up for service, you will be notified of your contract in one of two ways at a minimum. When you call, the sales agent goes over a brief summary of the contract, including cancelation costs, and agents make disclaimers depending on previous answers the customer gave them. If the customer provides a valid email address during the sales call, they will get an email from Hughesnet that contains a link to the contract in full.
If you sign up online, you are required to submit an email address, and you are told point blank about the contract at several points in the sign up process.
The last time I had a terminal go through its activation, it actually brought up contractual information before it would allow me to go online. The moment that the terminal sees you select "Accept" is the moment you agree in full to the contract.
If you would like to view your mothers contractual terms and conditions, then you will find everything at http://legal.hughesnet.com