There are a number of incidents in world history, some verifiable, some dubious, of similar massacres during events of hospitality. Vlad the Impaler of Romania supposedly murdered many of the unruly noble vassals of Transylvania after inviting them to a feast, for example. Genghis Khan's father, Yesugei, was poisoned at a wedding feast, when Genghis was just a young boy.
In general, most rulers prefer to avoid violations of hospitality because this leads to an atmosphere of fear that makes negotiation nearly impossible, and negotiation is the foundation of both explicit truces and implicit peace outside of wartime.