It is acceptable to let long text flow into adjacent cells on a worksheet when —

Concept: A text entry always belongs to exactly one cell; what changes is how much of it the worksheet draws. A left-aligned text entry that is wider than its own column is rendered across the neighbouring columns, but only while those neighbouring cells are empty. As soon as a neighbouring cell holds a value of its own, the display is clipped at the column border — the full string is still stored and is still shown in the formula bar, but the reader sees only the part that fits.

Applying it here: So letting a long label spill is safe exactly when the cells to its right will stay empty: nothing is hidden and no column has to be widened. If those cells are going to receive entries of their own, the overflow display disappears the moment they are filled and the label is cut off at the border. The acceptable condition is therefore that no data will be entered in the adjacent cells.

Cross-check — what the other listed conditions govern:

• Data will be entered in the adjacent cells — the neighbouring entries occupy their own columns and the long label is clipped at the border.

• There is no suitable abbreviation for the text — abbreviation is a wording decision; it changes how many characters the label contains, not the rule that decides whether an entry is drawn past its own column.

• There is no time to format the text — available time is a constraint on the author's schedule; a formatting tool such as column width, Wrap Text or Shrink to Fit behaves the same way whenever it is applied.

• None of these — one of the listed conditions does describe when the overflow display is safe, so the set-level negation does not hold.

Long text may therefore be allowed to flow into adjacent cells when no data will be entered in those adjacent cells.