What is a model release form?
By law, if a photographer, or anyone else, wishes to make photos public, for sale or promotion, then any people who are recognisable in them must give their consent in writing.
This is common practise for working models, who are being paid to be in the pictures, after all. But if you are looking for a wedding photographer, you are paying them for their time, not the other way round.
Why do I need to be careful?
If you sign a model release form as part of your contract, you're giving the photographer the right to display and print your photos for whatever they want, including money.
What can I do?
As a paying customer, you are not obliged to give your consent - so check the contract carefully, and if you don't want to sign away any your rights, make sure they cross out the model release section,
Otherwise you could see your photos used anywhere, for example on a blooper site, or making money in a brochure and you not seeing a penny.