To clear up a few items in this now old post. There seems to be some confusion on the rules and laws regarding the signs of liquor establishments. The sign above that was referenced as a "photocopy of a real sign" is in fact a real sign that holds the force of law. See the bolded sections below.
There are two signs available to liquor license holders per RLD (Regulation and Licensing Division)
No Firearms Allowed Poster
To be posted on all licensed premises that are licensed to sell beer, wine or spirits for on-premises consumption AND any establishment that has elected to prohibit firearms of any kind whether open or concealed, on its licensed premises.
No Firearms Allowed EXCEPT Concealed Carry Poster
To be posted on all licensed premises that are licensed to sell ONLY beer and wine and licensed premises that ONLY sell package alcohol for off-premises consumption, UNLESS the licensed premises has elected not to allow any firearms on its premises.
Secondly,
Signs do not have to be any specific size for them to hold the force of law if you are a concealed carry holder. The law you're referencing is part of the trespassing statutes NMSA 30-14-6 that has minimum standards that must be followed for a sign to be valid. Unfortunately, when you have a concealed carry permit issued or recognized by NM you subject yourself to NMAC "terms and conditions of license" (see the second paragraph below)
30-14-6. No trespassing notice; sign contents; posting; requirement; prescribing a penalty for wrongful posting of public lands.
A. The owner, lessee or person lawfully in possession of real property in New Mexico, except property owned by the state or federal government, desiring to prevent trespass or entry onto the real property shall post notices parallel to and along the exterior boundaries of the property to be posted, at each roadway or other way of access in conspicuous places, and if the property is not fenced, such notices shall be posted every five hundred feet along the exterior boundaries of such land.
B. The notices posted shall prohibit all persons from trespassing or entering upon the property, without permission of the owner, lessee, person in lawful possession or his agent. The notices shall:
(1) be printed legibly in English;
(2) be at least one hundred forty-four square inches in size;
(3) contain the name and address of the person under whose authority the property is posted or the name and address of the person who is authorized to grant permission to enter the property;
(4) be placed at each roadway or apparent way of access onto the property, in addition to the posting of the boundaries; and
(5) where applicable, state any specific prohibition that the posting is directed against, such as "no trespassing," "no hunting," "no fishing," "no digging" or any other specific prohibition.
C. Any person who posts public lands contrary to state or federal law or regualtion [regulation] is guilty of a petty misdemeanor.
History: 1953 Comp., § 40A-14-7, enacted by Laws 1969, ch. 195, § 2; 1979, ch. 186, § 3.
NMSA 10.8.2.16 (F)
Carrying prohibited on private property. In addition to other limitations stated in the act, a
licensee may not carry a concealed handgun on or about his person on private property that has signs posted
prohibiting the carrying of concealed weapons or when verbally told so by a person lawfully in possession of the
property.
The above section does not place any burden on the poster to comply with NMSA 30-14-6 which is strange considering 10.8.2.27 does charge the poster with complying with the posting requirements.
10.8.2.27 - PROHIBITING THE CARRYING OF CONCEALED HANDGUNS ON PRIVATE PROPERTY: Pursuant to Subsection C of NMSA 1978 Section 29-19-12, any person lawfully in possession of private property may prohibit the carrying of concealed handguns on such private property by posting notice in accordance with NMSA 1978 Section 30-14-6 or by verbally notifying persons entering upon the property.