Currently in the system it is possible to delete WBS tasks, which have related posted transactions. If we do so, the system does not allow us to publish the WBS and throws an error: You have deleted tasks from the WBS that have actuals reported against them. Publishing has failed and the WBS is still in draft and view differences has been enabled.

Workaround is not useful as user looses all modifications made in WBS: If any user deletes one or more WBS lines, which have related posted transactions, the only solution is to restore the WBS to the last published version, but doing so entails the loss of all the modifications the user has done to the WBS. So, it is not a proper workaround.

Product team confirmed this is the design of the system, because if you delete an activity which has posted transactions against it, you break database referential integrity. Publish is already blocking the deletion. 

However, user would prefer the Delete button to be blocked in those type of cases to avoid difficult situations.