Ir is indeed a violation of Masonic law for an Arkansas Mason, under the jurisdiction of the Grand Lodge of Arkansas, to be an active member of Shriners International, to petition the Shrine, to communicate Masonically with Shriners, or participate in any function sponsored by the Shrine or held in the Shrine Temple (Section 2.1.42 of the Arkansas Digest of Laws, and as explained in a series of letters of clarification). This extends outside the state, for example if I go visit my sisters in Texas or Mississippi, I am still prohibited from visiting any Shrine facility or function.
For example, our lodge has a fundraising project in which we operate the concession stands at Baron Coliseum on the state fairgrounds for events at the Coliseum. This weekend, the Shrine Circus leased the coliseum, ad we were needed for the concessions. We had to get a dispensation from the Grand Master in order to fulfill our running contract with the coliseum, since a Shrine function would be going on there. In fact, I just got back from working the last night there... Shrine in Arkansas is no longer a Masonic organization; since last year they have been able to take just about anyone off the street and make them Shriners, without being Masons first. Since they allow non-Masons to attend tyled meetings, the entire Shriners International is clandestine within the jurisdiction of Arkansas.
But dimits are still a function of the Secretary in the local lodge, and the Grand Master doesn't have anything to do with them under ordinary circumstances.