Since you decided to force the creation of a specialized Dimensions layer on us when a dimensions is created (and here is a feature request to make this optional: http://illustrator.uservoice.com/forums/333657/suggestions/48236954), we now have a problem with accidental creation of art directly in this dedicated layer, since every time a dimension is selected, this layer gets active and unlocked (reported here: http://illustrator.uservoice.com/forums/939477/suggestions/47570813)

Since you probably don’t really care, and won’t solve both issues, perhaps you should keep this layer locked and not unlock until we choose to.
Perhaps you should make the Dimension tool lock-agnostic then, and allow it to edit and created dimensions in this locked layer (which will prevent every other tool accessing it).

Do something already.