In other cases, installing a sleeve in the construction element where it passes through a PEX tube is necessary in order to be dismantled when the need of a PEX tube without destroying the element. Criterion, of course, not unambiguous. If the need is dictated by force majeure, then, as practice shows, such cases are extremely rare. And to equip each building element (of many millions) cartridges is unlikely to be useful. If you bear in mind the complete replacement of polymer piping (the life which, for example, in cold water, is 50 years old, and PEX radiant heating - 25 years), the appropriateness of the use of such shells is also not clear.
Requiring mandatory sealing the space between the PEX pipe and sleeves to be established in the building elements, of course, true. This must be done in order to exclude the penetration of odors and insects from one room to another. Clearly, insects (bedbugs and cockroaches) should not penetrate to the neighbor. Also, do not want their possible movement, for example, from the kitchen to any room.