Subrepositories in Mercurial

If one populates a folder within a project by way of a subrepository it opens the door to some danger. A commit at the top of the consuming project will cascade to commit changes in the subrepository folder as well making such a pattern not so great for scenarios in which one project needs to consume a library that is another project without altering it. The ways to fix this shortcoming may lie in merely permissions for the subrepository for only the right users or there may be a setting for labeling the subrepository as commit-impaired, but such a setting would have to be prepped properly by the individual crafting the call to the subrepository to begin with.