I have 3 gd accounts, no problems. Not much reason to have multiple accounts other than to maybe help split up sites. They most likely can link them if you violate policies so I wouldn't think it provides much advantage other than convenience.
generally web hsoitng companies allows you to keep as many accounts as you want. This is generally useful for web designers/developpers that manage the accounts of their customers separately
As a mistake when ordering accounts I accidently created 7 accounts. Same info just different customer numbers.
No ban was ever imposed.
You are safe but if you call godaddy they will consolidate it for you. Their customer support is actually pretty good. Almost as good as lunarpages ;-)