In US Patent law have provisions for false marketing:-
35 U.S. Code § 292 - False marking
(a) Whoever, without the consent of the patentee, marks upon, or
affixes to, or uses in advertising in connection with anything made,
used, offered for sale, or sold by such person within the United
States, or imported by the person into the United States, the ...
Patent pending means that either a provisional patent has been filed or a non-provisional has been filed and has not been finally rejected, abandoned, or issued. Provisional patents are only valid for one year and do not get published. Assuming there is no national security restrictions, all non-provisional US patent applications are published after 18 ...