Yes they appear to have become common practice over the last 15 years or more. The problem of course, is that any "agreement" requires two or more parties to "agree".
Unless you were lawfully incompetant when you entered into the agreement because for example you were underage or had diagnosed mental impairment, then a challenge is always going to be difficult. If you were coerced in some way or threatened you might have a strong case. Unfortunetaly being greedy, impatient, ignorant or ill advised is not a very strong basis for a challenge. It is normally a case of caveat emptor when anybody is selling you something. In the case of being sold something with a written contract, you should certainly read and understand the terms and wherever necessary get proper advice before signing on the dotted line.
"Ridiculous agreements", are not necessarily unlawful agreements and it does beg the obvious question, how ridiculous was the party that signed up to something they deemed as such ?
Having said that the courts are full of people challenging contracts of all types, and if you feel you have a case take it to a professional who will be able to give you sound advice and (after signing an agreement) be able to act for you. Far better than any anecdotal advice you will receive here. However a point to bear in mind is that win or lose, it will likely take longer to be decided than the 2 years of your bond.
Good luck.