WinSCP setup creates registry key "HKCR\Software\Martin Prikryl\WinSCP 2" to ensure that registry storage is used. But this forces it only for the user that have installed WinSCP. The same key should be create in HKLM to ensure that registry is used by all users. Otherwise an INI is used in installation directory, hence shared by users, what may not be desired behavior.
1) User preferences set in installer are stored to HKLM (when installer is run by administrator) and used as defaults for all users.
2) Side effect of above is that WinSCP HKLM key is always created, what make WinSCP use registry storage for all users (not only the one that has installed WinSCP).
3) Option to add WinSCP path to search path is not offered if installer is not run by administrator.