Does the marking of products as being patented entail any risks?
Extreme caution is called for if the product is to be offered for sale simultaneously in countries where a patent has been obtained or applied for and in countries where no patent is pending or where no patent has been applied for respectively where a patent has expired.

To be avoided therefore is giving the false impression of having protection in countries in which no patent protection exists or has been applied for. Such an improper use of marking is deceptive and may have penal consequences in most countries (including Switzerland).

Thus a clear indication of the countries for which a patent has been granted or applied for is advisable, e.g.:

US Pat. No. XXXXXXX; EP Pat. Pend.; etc.

In case of expiration of patent protection, the marking must be removed immediately from the products to be marketed (which might cause major difficulties in practice, of course).