Yes, it appears to be legal in your state: your state does not appear to have any laws setting a minimum shift length or durartion (unlike some other states, which do), which means that even if it is economically bad for you, your employer can all you in for just 15 minutes. You may need to look for other employment if this happens often enough as to make the job not worthwhile.Unfortunately, except when you have an employment contract, employment in this country is "employment at will." That means that your employer decides the hours you work.