How best to add/remove selections

Here is an simple example using local variables:

a!localVariables(
  local!checkBoxesFromDB: {
    a!map(id: 1, value: "ITEM_1"),
    a!map(id: 2, value: "ITEM_2")
  },
  local!checkBoxValue: local!checkBoxesFromDB.value,
  local!checkBoxesToAdd,
  local!checkBoxesToRemove,
  {
    a!checkboxField(
      label: "Check box field",
      choiceLabels: { "Item 1", "Item 2", "Item 3" },
      choiceValues: { "ITEM_1", "ITEM_2", "ITEM_3" },
      value: local!checkBoxValue,
      saveInto: {
        local!checkBoxValue,
        a!save(
          local!checkBoxesToAdd,
          a!forEach(
            items: local!checkBoxValue,
            expression: a!map(id: fv!index, value: fv!item)
          )
        ),
        a!save(
          local!checkBoxesToRemove,
          difference(
            cast(
              typeof({ a!map() }),
              local!checkBoxesFromDB
            ),
            cast(
              typeof({ a!map() }),
              local!checkBoxesToAdd
            )
          )
        )
      }
    )
  }
)

The "best practice" (IMHO) is to not remove but instead deactivate rows that a user un-selects in this manner (via an "active flag" row or a "removed flag" row, both the same thing except for being opposite in value).  The question then becomes, what happens if a user re-selects previously un-selected rows?  The code is a little trickier but it helps prevent DB rows from getting spammed if you implement a system that looks up any deactivated rows for the current user and marks them as re-activated if they're re-selected (instead of selected for the first time).  IMHO it's worth the time and hassle to implement.