Firstly, is it still the case in Excel worksheets that "locked" cells are only protected when worksheet protection is engaged? (I use Excel 2013, but the circumstances on which I am writing may have been subverted by later versions.)
If that is the case, I have a suggestion to improve this.
Only yesterday (28 June 2015), I had an instance, while using Excel 2013 to collect and tabulate the results for a chess tournament, where I twice accidentally overtyped a cell containing a formula despite these cells being "locked", which meant
that one of the teams involved was given a lower score than achieved in one of the matches and, as a result was shown as finishing in a lower position in the table than if the data had been entered without error.
This was my mistake. During the event - which took place during the morning 10:00 - 13:00, but involved 11 matches (it was "blitz" chess) - I had reason to turn off worksheet protection to make a modification to part of the reporting system. I
forgot to turn protection back on before entering more results, allowing the erroneous overtype to be possible.
If the protection system for cell formulae is still as described in my first question, then surely it is high time this was addressed, because mistakes can happen. On considering this question, I find it odd that in a tool as advanced and powerful as Excel
has become, security of cell formulae is still at this same "primitive" level.
My suggestion is this: a locked cell should ALWAYS be locked, without the need for the separate action to turn on worksheet protection. This can easily be done, i) When a formula is entered into a cell, the protection for the cell should be
automatically set to "locked"; ii) "locked" should MEAN "locked" - this security should be active immediately, so that the cell cannot be overwritten without requiring the user to remember to protect the sheet; iii) if the formula
needs to be modified (or deleted), provide the means by right-clicking the cell and give access to a context menu selection to 'edit the formula'; iv) immediately the edit is finished, the cell is re-locked and cannot be overtyped.
This suggestion will render formulae secure without requiring the user to exercise a specific discipline which, in situations where data input is required to be undertaken quickly or under pressure, an oversight in engaging worksheet protection can lead
to errors.