No this is not possible with Joomla.
There are several options for you to achieve the same result, I list them in order of ease.
Use joomla redirect component. Simply tell the user to surf to the url he wants, he will then find it in the administrator - components - redirect, where she can insert the non-sef url.
Tell them to use a different prefix: i.e. create a hidden menu where they will add the direct links;
Additionally, in order to remove the id from the url you can:
Install simplecustomrouter extension, it should do the job out of the box but some coding may be required on your part in order for it to work properly; extremely lightweight.
Go for a blasoned SEF extension such as sh440sef, this will add some overhead and may require a lot of work in configuration.