Karina is excited for the big day. Her dress is ready and the invitations are out.  But her wedding photographer? That's not such a pretty picture. She had one lined up, but got out of the contract, which had a cancellation period.

"I just kind of was uncomfortable with their lack of responses and their kind of run around," she said.

Karina wanted to warn other brides so she posted an online review.  Soon after, she got an email from the photographer saying, "We kindly ask that you remove your posting."  The email noted she could face "legal action" for "breach of contract." 

Karina says she never realized her agreement said:  "...Neither party will disparage the other."   

"I was livid," said Karina. "I was so upset that: a.) I couldn't review a vendor, b.) That you would email me, almost threateningly, so I felt- like I think I felt bullied."

Anja Winikka, of TheKnot.com, says these non-review clauses are popping up in contracts for all sorts of wedding vendors, limiting what couples can say.   

"Prohibiting them from giving them a review that's less than a 5 star review," added Winikka.

And like Karina found, these clauses can be hard to spot.   Experts say be on the lookout for words like "confidentiality" and "non-review."

"If you see "non-disparagement" in your contract that's a cause for alarm," Winikka said, as another term to watch out for.

Attorney Noah Davis says he's alarmed these clauses are now used by some contractors, plumbers and dentists. Even some online merchants are putting them in their terms and conditions.

"I really am floored by the prospect that this is happening," said Davis.

Experts say it's happening because a company's online reputation can make or break the business and some try to protect themselves against unreasonable customers. Davis says the law is still evolving when it comes to these clauses.

"It's hard to really put, put a finger on how the courts are going to rule on these sorts of things," said Davis.

Experts say you should never sign a contract until you understand everything in it.  If you spot a non-disparagement clause, ask the business why it's there. And if you really want to hire them, negotiate.   

But Davis' advice is: "Don't sign those agreements if they don't allow you to take those clauses out of the contract."

Karina removed her online review to avoid legal headaches, but worries this trend will result in other brides not getting the full "picture" when it comes deciding who to hire for their big day.

"It's a huge game changer if you really can't speak freely about your experiences with some of these businesses," she said.

Winikka says be cautious when you read online reviews that are all glowing or a bit over-the-top. She says that could actually be a red flag. Instead look for reviews that seem balanced, and if there's a negative review, look to see if and how the company responds. If they respond to consumer complaints in a reasonable way, she says that's actually a good sign.