A nabbash is a person who opens a grave and takes the burial shroud. The footnote contrasts this case with tarrar because some features ordinarily associated with theft are different in this setting.
The source describes a deficiency in correspondence with the ordinary notion of theft and therefore does not attach nabbash to sariq in the same legal ruling. This is the textbook’s jurisprudential illustration, not a complete comparison of positions across legal schools.
Taken together, the two examples show how an unusually strong or weak resemblance to the basic category can create obscurity of application. They do not, by themselves, resolve every associated juristic ruling.