Server Administration :: Logging In As SYS?

I've been an Oracle DBA for almost twenty years. In that time I have worked in various organisations - sometimes as a "permanent" employee (although nothing is permanent these days ) and other times as a contractor. I have been in my current role for the last six months since being made redundant from my last position.

In this organisation we support a lot of Oracle databases on many different servers spanning various networks. There are two DBAs who have been here for several years

However, they are both in the habit of logging in as SYSDBA for everything. They find it amusing that I refuse to do so for daily administration as I know that this is bad practice. Import and exports are even taken as SYS. Whenever I mention that it's bad practice they shrug it off saying that they've been doing it for years with no problems.

So I have been scouring Tahiti and Metalink looking for a definitive document from Oracle that states just why this is such bad practice. I would imagine that an import as SYS could have catastrophic consequences for the data dictionary if you're not careful, but I can't think of much else.

We've all seen Michel's default "just don't do it" message whenever a poster mentions that they have done something as SYS.