Almost every site has a cookie banner and a large share of them do nothing at all. They are installed, they appear, they store a value saying the visitor clicked, and the tags behind them fire exactly as they did before. This is not usually dishonesty. It is that installing the banner and wiring the tags to it are two different jobs, the first takes ten minutes and the second is fiddly, and nothing on the screen tells you that the second was skipped.
The four checks that settle it
One: on a fresh visit, before any click, does the storage panel stay empty of everything except your own necessary cookies. Two: after refusing, does the network tab stop showing calls to the analytics and advertising endpoints. Three: is the decision written somewhere durable that names the categories chosen. Four: does the banner text match what the site actually does today rather than what it did when the banner was installed. A banner that passes all four is doing its job; a banner that fails the first is decoration regardless of its wording.
Why the tag manager is where this is won or lost
In most small company stacks the tags are loaded by a tag manager and the banner is one more tag inside it. That arrangement makes it easy to have the banner appear and the tags fire on the same page load trigger, which is exactly the failure above. Fixing it means changing the triggers so that the tags wait for a consent signal, and then testing rather than assuming, because a trigger that references a variable that is never set will fire rather than wait.
What to do when you inherit one
Do not start by rewriting the copy. Start by finding out what fires, what is stored and what is recorded, because that tells you whether you have a wording problem or a wiring problem. In our experience of auditing these, the wiring is wrong far more often than the words, and a site with plain honest text and correctly gated tags is in a much better position than a site with beautifully drafted copy over tags that never stopped.
Questions people ask about cookie banners
Does every site need a cookie banner?
Every site that stores anything non-essential and has visitors in a regime that regulates it. A purely static site setting nothing does not need one, and saying so is better than installing a banner that lies.
Is a banner enough on its own?
No. The banner is the interface. The compliance lives in what fires afterwards and in the record of the choice.
Can I use a free banner from my CMS?
Often yes for the interface. Check what it does with the decision, because the cheap ones frequently store a single accepted flag and offer nothing to read back later.