It is hard to say specifically because it is case by case. Normally it should affect the visa application and entry, e.g. the visa officer may ask her more questions, or not approve her visa application if she will apply for it in a short time (e.g. within one year), the IO at the port of entry may carefully check her document to make sure her travel purpose matches the visa type, etc.
Here are some websites for your information:
http://www.nolo.com/legal-encyclopedia/entering-us-what-expect-airport-29797.html
https://help.cbp.gov/app/answers/detail/a_id/757/~/friend,-relative,-etc.-denied-entry-to-the-u.s.
Here are some websites for your information:
http://www.nolo.com/legal-encyclopedia/entering-us-what-expect-airport-29797.html
https://help.cbp.gov/app/answers/detail/a_id/757/~/friend,-relative,-etc.-denied-entry-to-the-u.s.
