The Biblical passage that teaches the laws of me’ilah– the prohibition against deriving forbidden benefit from a consecrated object – teaches that these regulations apply to kodashei ha-Shem, i.e. only things that have been made holy to God (see Sefer Vayikra 5:15-16). Thus, both those things brought on the altar (e.g. sacrificial animals, meal-offerings), as well as those things whose value is consecrated for Temple upkeep fall into this category.
The first Mishnah in Tractate Me’ilah teaches that if a sacrifice became disqualified before its blood was sprinkled on the altar – one of the basic requirements of the sacrificial service – the animal retains its holiness and the laws of me’ilah will still apply to it. As an example, the Mishnah teaches that if kodashei kodashim (e.g. a sin-offering or a guilt-offering) were slaughtered in the southern part of the Temple courtyard rather than the northern part of the Temple, as required, the laws of me’ilah remain in force.
The Gemara explains that, in point of fact, in a case like this one the laws of me’ilah apply only on a Rabbinic level, paralleling this case with the case of a consecrated animal that dies, where we find that Ulla quotes Rabbi Yohanan as ruling that the laws of me’ilah do not apply on a Torah level, but that the Sages decree that they remain in effect on a Rabbinic level.
Generally speaking there is a principle applied regarding Rabbinic decrees that they are only put into effect in common situations, inasmuch as the Sages did not deem it necessary to establish decrees that would apply in unusual circumstances. The Perush Kadmon explains that in this case, even though it is unusual for the animal to die or for it to be slaughtered in the wrong area of the Temple courtyard, the Sages chose to institute this decree due to the severity of consecrated objects, and their understandable desire to limit the possibility that anyone would derive benefit from them.
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