I'm working on a new feature for our product, a component of which has some fairly major security implications: it runs as a WCF service, and performs some highly-privileged actions. As such, I'd like that component to only be installed when the user requires it (and removed when it's no longer required), and for the installation to be accomplished programmatically.
I've looked into advertising (specifically, assigned installs), and it appears to be a good mechanism for accomplishing this. I'm not sure whether the installation of an advertised feature can be undone, however, which would be useful for removing the component when it's no longer required. I'm also not completely sure whether programmatic installation could be achieved with advertising: advertised COM classes seems to be discouraged.
I'm wondering, therefore, if a simple call out to msiexec to install/remove the component would be more sensible. The component could be packaged in a separate MSI, or as a separate feature of our main MSI.
What techniques have you used for installing features on demand?