What else should we have to announce about ourselves and obtain explicit permission from homeowners before our otherwise welcome entrance is not a crime?
No, the proper way to handle this is either through standard trespass law without any special attention to lawfully possessed firearms, or--if firearms are going to get some special attention--the default position must be that a general invite makes entrance while armed lawful
unless the resident(s) gives notice that guns are not permitted.
Utah's 76-10-530 handles this quite well IMO:
76-10-530. Trespass with a firearm in a house of worship or private residence -- Notice -- Penalty.
(1) A person, including a person licensed to carry a concealed firearm pursuant to Title 53, Chapter 5, Part 7, Concealed Firearm Act, after notice has been given as provided in Subsection (2) that firearms are prohibited, may not knowingly and intentionally:
(a) transport a firearm into:
(i) a house of worship; or
(ii) a private residence; or
(b) while in possession of a firearm, enter or remain in:
(i) a house of worship; or
(ii) a private residence.
(2) Notice that firearms are prohibited may be given by:
[various means...]
As for businesses open to the public....same rules ought to apply to law-abiding gun carriers as apply to any other potentially unpopular minority group including racial/ethnic groups, religious or political affiliation, sexual orientation, sexual identity, gender, etc and so on.
Charles