Honestly...without knowing exactly what the problem is, it's hard to give a accurate answer. Things like weak shocks are not seen as overly dangerous but in the right conditions, they will cause the vehicle to react in an unsafe manner. For the most part, there's very little in a vehicles suspension that if it were damaged, it would be seen as still safe.
Damaged suspension can cause shocks and fatigue stresses to many parts of the car, especially the axle and possibly even the engine and related machinery. It is always best to get the suspension repaired.