No - it's not because multiple users are doing the same thing. The issue is that the particular design of the query makes the fields non updateable.
Eg - just open a simple query, and you will see that you can edit data directly in the query, thereby bypassing any checks you have within forms. Now if you take a totals query, you will find you can't edit the values in the query. Certain joins make a query non-updateable. The absence of indexes in tables can make a query non-updateable. So often you can get an updateable query by changing the way you approach the problem.