The following may not be registered as responsibility marks:
a.
symbols that do not meet the requirements set out in the Act or in the Ordinance;
b.
symbols that do not sufficiently differ from other symbols already registered;
c.
symbols that are in the public domain;
d.
symbols that offend against public order, common decency, federal law or state treaties;
e.
misleading symbols;
f.
official Swiss, foreign or international assay marks or hallmarks.