Slightly restricted mobility means you may notice minor stiffness during extreme movements like deep bending or high knee lifts, but it won't interfere with your normal skiing. Think of it like wearing supportive compression shorts — you're aware they're there, but they don't stop you from turning, stopping, or riding comfortably.
Most recreational ski hip protectors fall into this category because they use slightly thicker foam pads than the ultra-thin performance models. The trade-off is worth it for most skiers: you get solid impact protection with only a brief break-in period. Many people find the initial stiffness fades after a few days on the slopes as the protector conforms to your body.
If you're a casual to intermediate skier cruising groomers or skiing mixed terrain, slightly restricted mobility is perfectly fine. It only becomes a real concern for racers or aggressive carvers who need absolute freedom of movement for peak performance.