Generally anything related to the Olympics or sport is risky. But there are many exceptions.
Search for information about their lineage, goals, and lead organization of the martial arts school. The more popular schools generally have consumer reviews, and information about their goals. Observe the sparring, and kindly ask the instructors about how they fulfill full contact training. Technically most full contact schools (regardless of style) have a point system of some sort. The problem is whether or not the sparring is continuous, realistic, and moderate to full contact. If there are frequent pauses after clear strikes and the strikes are soft: Don't bother. It should resemble a fight, and be a realistic speed. No raised flags or scoreboards.
Full contact Tae Kwon Do isn't a very popular approach now. Most Olympic schools teach watered down foot fencing. But some schools still teach it the way it should be. Just keep that in mind. Blaming the style is throwing the baby out with the bathwater. But if the black belts are sloppy, young, and can't throw a hard strike to save their life: Get out of there.
You're a consumer. Decline them if they can't help you.