Yup. Rand() chooses a random float value for each entry. By default I believe it’s anywhere between 0 and 1. So it may divide the first bill by .76, then the second by .23, then the third by 0.63, etc… So you’d end up with a completely garbage database because you can’t even undo it by multiplying all of the numbers by a set value.
On the other side of the same coin: When I mass edited my comments before quitting Reddit, I got site-banned. Basically, my first account’s automated edit got me auto-banned from several subs with pro-spez mods. Some subs had set their automod to detect when people were using the more popular methods of auto-editing, and set the automod to ban for using them. Then when I did the same with my second (and third, and fourth, and fifth, etc…) account, it almost immediately got site-banned for ban evasion.
Basically, account 1 was banned from a sub, so when account 2 started doing the same thing on the same IP address, it was flagged as ban evasion. And ban evasion is one of the few things that will get you banned site-wide instead of just from a specific sub.
I went back and checked a few months ago, and all of those site bans were lifted and the edits were undone. Likely because a site ban prevents the comments from showing up (which hurts Reddit’s bottom line, because they show up as a bunch of [removed] comments instead,) but also prevented any of the edits from actually being published. So when they lifted the site ban (to get those old comments to show back up again) it was as if I had never edited them at all. I had probably a million karma spread across my various accounts. I was extremely active at one point, so Reddit had a direct incentive to unban those accounts with literal thousands of comments.