If client loses class 35 registration for the O-logo, it doesn’t mean client cannot use the O-logo in their store and sell their own labelled products. But without class 35 registration for the O-logo, others may register and use the same or similar logo in their stores (such as on the shop sign) selling jewelry, which will surely cause confusion among the public. Also, client may face the risk of being accused of trademark infringement for using O-logo on the shop sign of the store, even we may argue it’s a proper use of our registered trademark.