impact of completed sprint values removed from sprint field

[Anita Szabo]

Hello there, 

Until now, completed sprint values were stored in the sprint field, however with the arrival of some new team members, I noticed that they started removing completed sprint values on some issues. Is there a knowledge article that mentions the impact of this or do you know if it has an impact, if any? Is it best practice to keep the completed sprint values? 

The other aspect of this, is that while sprint create/manage/start-close permissions are locked down to a specific user groups, it seems that anyone who can edit issues in the project can also edit the sprint field. Wouldn't this be included in managing the sprint? If managing sprint project permission does not drive the sprint field edit, how could I lock this field down to the same user group please? Any pointers would be greatly appreciated. 

Thank you