One solution, available in most languages, is to not use manual indexing at all. Use a for-each loop, iterator or similar abstraction. Sometimes using an index

One solution, available in most languages, is to not use manual indexing at all. Use a for-each loop, iterator or similar abstraction. Sometimes using an index or counter is unavoidable, of course, but hopefully seeing an indexed loop, especially combined with a comparatively risky operation like banning, would trigger more scrutiny during a code review, more testing, or both. Avoiding manual indexing doesn't prevent you from sticking other stray integers in place of user IDs (like specifying message IDs instead of the user ID that sent the message), but most of them are not biased toward the start like indexes are. Still, I think it's prudent to avoid these kinds of errors at all if you can. Perhaps a good reason to switch to UUIDs for all primary keys, even if the normal concerns about enumerability don't apply.