Free running rigs are the safest option but semi fixed are more commonly used and prefered by the majority of anglers, I think if you check the rig is ineed 'semi' fixed and the pressure needed to free the set up is minimal then it's going to be as good as it can be expected.
As I said earlier it's more a case of when the rig is lost that it can become dangerous, small fish are unlightly to cause a break but a small fish taking the rig into a snag has as much chance as a large fish of causing a breakage. If the rig can seperate under light pressure then fine, the answer is to check and double check the ease with which a rigs componants can be dissassembled with gradual forward motion.