In Utah it’s not against the law to carry into a place that has signs up, they can however ask/tell you to leave because you have a firearm and you have to leave or they can have you arrested for trespassing
Utah State Law.
76-8-311.1. Secure areas – Items prohibited – Penalty.
(1) In addition to the definitions in Section 76-10-501, as used in this section:
(a) “Correctional facility” has the same meaning as defined in Section 76-8-311.3.
(b) “Explosive” has the same meaning as defined for “explosive, chemical, or incendiary device” defined in Section 76-10-306.
(c) “Law enforcement facility” means a facility which is owned, leased, or operated by a law enforcement agency.
(d) “Mental health facility” has the same meaning as defined in Section 26B-5-301.
(e) (i) “Secure area” means any area into which certain persons are restricted from transporting any firearm, ammunition, dangerous weapon, or explosive.
(ii) A “secure area” may not include any area normally accessible to the public.
(2) (a) A person in charge of the State Tax Commission or a correctional, law enforcement, or mental health facility may establish secure areas within the facility and may prohibit or control by rule any firearm, ammunition, dangerous weapon, or explosive.
(b) Subsections (2)(a), (3), (4), (5), and (6) apply to higher education secure area hearing rooms referred to in Subsections 53B-3-103(2)(a)(ii) and (b).
(3) At least one notice shall be prominently displayed at each entrance to an area in which a firearm, ammunition, dangerous weapon, or explosive is restricted.
(4) (a) Provisions shall be made to provide a secure weapons storage area so that persons entering the secure area may store their weapons prior to entering the secure area.
(b) The entity operating the facility shall be responsible for weapons while they are stored in the storage area.
(5) It is a defense to any prosecution under this section that the accused, in committing the act made criminal by this section, acted in conformity with the facility’s rule or policy established pursuant to this section.
(6) (a) Any person who knowingly or intentionally transports into a secure area of a facility any firearm, ammunition, or dangerous weapon is guilty of a third degree felony.
2 things here:
(ii) A “secure area” may not include any area normally accessible to the public.
and
(4) (a) Provisions shall be made to provide a secure weapons storage area so that persons entering the secure area may store their weapons prior to entering the secure area.