The military has been recruiting in schools for many years. In some cases, depending on the student and their home financial situation, the military may be the only way the student will be able to pay for continuing education. The military offers various benefits to include college and health benefits. In the end parents have to give the recruiter permission to speak with any child under the age of 18, so the control still remains with the parent. With this in mind, I do not believe that parents will have a real issue with military recruitment in schools.
Although not everyone will be interested in joining the military, it is useful to give students information about a variety of career paths, including military careers. As with all career and higher education information, the content should be monitored to make sure that it is accurate and doesn't pressure students. As with other potentially controversial subjects, the schools could give parents an opportunity to opt their children out of such activities.