I'd say, yes, in that a good many breeders have high cash penalties in their contracts if the buyer doesn't spay/neuter and provide proof they did so by a certain age. However, 4 to 5 months is extremely young. Most breeders make that 6 months. More and more are going for a year, and one breeder I recently emailed with agreed to 18 months (I'm starting a puppy search). The good breeders have read the research, just as those of us looking for puppies have. The problem for the breeders is they really, really don't want the puppies they sell as pets bred, and the older the puppy gets still intact, the greater the chance of an accidental breeding. Right in this forum there have been posts by people playing with fire and letting a bitch in heat stay with an intact male, sure they can stop a breeding because they're in the same room.
Also, while I've seen financial penalties in contracts before, I've never seen one that high - one I saw recently at $12,000 struck me as ridiculous. If the buyer fought it, I sincerely doubt any court would enforce it. That's the problem with a lot of breeder contracts. They contain provisions no court is going to enforce, and the breeder is probably not going to put out the money to sue anyway. The contract is just a way of trying to make sure the buyer adheres to certain standards.
That said, I personally read anything before signing and absolutely do not ever sign anything I'm not willing to abide by even if the most unlikely situation unfavorable to me arises. Defending the most frivolous lawsuit would be expensive and stressful.