Cut Hair Dry

Dry hair cutting - Van Loenhout
Q: When you go to a salon to get your hair cut, is it safe to cut the hair when it is dry or is it always better to wash the hair first? I got my hair cut last week and she insisted that it was easier for her to cut it when it was dry to make sure it came out even.
A: While it is not necessary to wash the hair before cutting it, most stylists will at least wet the hair.
This is usually done because cutting dry hair with shears or a razor causes small hair fragments to scatter all over. These tiny hair segments can become imbedded in the skin and get infected in a worst case scenario, or simply result in itch at the very least as they get into the clothing and begin to irritate the skin.
That being said, if your stylist feels more comfortable working with dry hair while performing a precision cut, there is nothing wrong with doing so, just as long as she makes sure to protect you from the scattering hair fragments.
Personally, I can see where certain hairstyles might be easier to make perfect if the hair is dry when being cut. Styles such as a blunt-cut bob on wavy hair would be easier to get perfect when you know that the hair's length isn't going to change once the hair is dried.
The variance between the lengths of the hair when wet as opposed to dry can be as much as 1-1/2 to 4 inches depending on the amount of curl in the hair and the overall length.
Unless her cutting your hair dry was causing you discomfort, or she wasn't taking precautions to protect you from the hair fragments, I wouldn't be overly concerned about the situation.
See also:
What will give the best results: dry haircutting or wet haircutting?
How does hair elasticity affect a haircut?
Is wet hair more prone to hair loss?
Should you not brush hair when wet?