Nobody Decides to Go Off-Brand
Every brand drifts a little each time somebody needs a post by four o'clock, and AI has made four o'clock come round a lot more often.
How it actually happens
Here's the version I see most often. A business pays for a proper brand, guidelines and all, and for the first month everything that leaves the building looks right. Then somebody needs a recruitment post by the end of the day while the designer is on holiday, so they open Canva, find something close, swap the green for one that looks about the same on their laptop, and nudge the headline up a size because it felt a bit timid. It looks fine, it goes out, and nobody minds, because it is fine.
The next person doesn't start from the guidelines, though. They start from that post, because it's the most recent thing and it's sitting right there in the shared folder. They change one more small thing for a perfectly good reason, and the person after them starts from theirs. Six months later nothing coming out of the business looks quite like the brand it paid for, and at no point did anyone do anything you could reasonably call wrong.
A photocopy of a photocopy
Anyone who worked in an office in the nineties knows what happens when you copy a copy. The first one is nearly as good as the original, the fifth has grey speckles down one side, and by the tenth the letterhead has gone fuzzy and someone has written the phone number back in with a biro. No single pass did much damage. The loss lives in the compounding, while the original sits perfectly safe in a drawer that nobody opens.
Brand guidelines are that original. A forty-page PDF is a lovely thing to receive and almost nobody reads it twice, because when you're making something in a hurry you copy whatever is in front of you, and the guidelines are in a folder whose name you can't quite remember.
AI makes more copies, faster
The new tools have changed the speed of all this far more than its nature. A post, a slide deck or a set of social graphics now takes seconds, so a team that used to make five things a week can make fifty, and every one of them is a fresh copy taken from whatever happened to be nearest. The output is polished, which makes the drift harder to spot than it used to be. Wonky alignment and a stretched logo gave the game away. Competent, plausible and very slightly off gives nothing away at all.
The direction of the drift has changed too. When a person goes off-brand they tend to wander somewhere personal, towards a font they like or a colour from their last job. When a machine does it, it heads for the middle, because the middle is what it learned from: tidy, well lit, reasonably professional, and indistinguishable from the business down the road using the same tool with the same prompt. Leave a brand to the machines for long enough and it ends up looking like the average of everyone else's, which is about the most expensive thing a brand can look like.
Pave the shortcut
Planners have a name for the muddy track that appears across a lawn where people cut the corner instead of using the path. They call it a desire line. You can put up a sign asking everyone to keep off the grass, and you'll be looking at the same muddy track next spring, or you can accept that people will always take the quickest route and put the path where they're already walking.
Most people going off-brand are cutting a corner because the on-brand route was slower, and a stern paragraph in the guidelines does about as much good as the sign on the lawn. What works is making the right route the quickest one. In practice that means templates where the colours, type and logo are locked and only the parts that should change can change, a brand kit loaded into the tools people already use so that the nearest option is also the correct one, and a short set of rules written plainly enough that the tools, and whoever is prompting them, can follow them without a design degree. None of it is glamorous, and it rarely gets mentioned at the launch. Most of the work is deciding in advance which choices nobody should have to make at ten to four on a deadline.
What this means for your business
If your team already makes its own material, I wouldn't try to stop them. It's usually the sensible call, it's certainly the cheaper one, and the people closest to your customers often know exactly what needs saying. What's worth protecting is the part they shouldn't have to think about.
A useful test is to pull out ten things your business published in the last month, lay them side by side, and ask whether a stranger would know they all came from the same company. If they would, lovely. If you catch yourself explaining that one was a rush job and another was made by someone who has since left, that's the drift, and it has been costing you in the few seconds a buyer gives you for rather longer than you've noticed. It's one of the more common ways a business gets better while its brand goes the other way.
The brand you paid for is still in the drawer. The one your customers actually see is whatever somebody made most recently.