The current rule is that Hala/Ysgard characters must worship a god in order to be granted divine spells.
The Hala team does visiting characters the courtesy of assuming that they are properly in favor of whatever Power is granting them spells on their homeworld. If you are from another world, and are out of favor or for some reason restricted in your divine spellcasting there, coming to Hala/Ysgard and casting such spells here is an exploit. Do not do this.
Arkaz is planning on implementing a script to restrict the casting of divine spells granted by Arkaz gods to the proper classes & alignments (http://www.arkaz.org/viewtopic.php?f=8&p=68775#p68775
). This script will also be implemented here, but does not affect the rules above.