Protection.AllowInsertingColumns Property (Excel)
Returns True if the insertion of columns is allowed on a protected worksheet. Read-only Boolean.
An inserted column inherits its formatting (by default) from the column to its left, which means that it may have locked cells. In other words, users may not be able to delete columns that they have inserted.
The AllowInsertingColumns property can be set by using the Protect method arguments.
This example allows the user to insert columns on the protected worksheet and notifies the user.