There have long been 'legends' of various liberal figures in Judaism, including Yeshayahu Leibovitz (brother of Nechama Leibovitz) that would 'skip' Purim. On the 14th of Adar they would be sure to be in Jerusalem, while on the 15th of Adar they would be sure to be outside of Jerusalem, thereby avoiding the halachic requirement of fulfilling the mitzvah of Purim. The reason given is that Purim can be perceived as an 'immoral' holiday, celebrating the murder of tens of thousands members of the Persian empire at the hands of Jews (though possibly explainable as self-defense).
a) I've seen multiple sources referring to this story, some claiming it as fact, others claiming it as fiction. Does anyone have any clear cut sources on the matter?
b) Is there any reference in halachic literature to such a practice? Is it explicitly looked down upon? How about the more general idea of putting oneself in a position in order to be exempted from a mitzvah?