Many websites today have autoplay video/audio ads, even when they aren't supposed too. This post at the webcomic Erfworld lays out the basics as to why. In short, advertising networks are paid for ads from producers and host them on their networks. The networks appear on many sites, and those sites receive a portion of the revenue from the networks.
It turns out that the best-paying networks "accidentally" let a larger portion of "malicious" (that is, with unauthorized function) ads through. These ads play audio when the websites running them have demanded no-autoplay, crash websites with long scripts, lock the page so the ad is on-screen, making it impossible to scroll and even redirect mobile devices to the purchase page of whatever they are advertising. Somehow, the networks that pay less don't have the problem of "malicious" ads "sneaking through" and "accidentally" breaking webpages or blasting noise and music.
At the moment, these ad companies are protected. The obnoxiousness of the ads is often related to the uselessness of the product, so annoying or even destructive ads enhance revenue - the terrible reputation of the company is not a factor for someone selling a cell-phone game no one has heard of. Most people won't quit a website for playing an audio ad sometimes, so the ads still get plenty of viewers. Even if a website goes down, the ad networks are massive - killing a smaller website won't noticeably impact a network's revenue stream. Finally, the ad network is not the company selling the particular product, so even if the product is some people would normally buy and runs the risk of a boycott, the network itself is safe, because no one knows who it is.
So what options exist for people to avoid destructive, harmful, annoying or otherwise destructive ads.
1) Get an ad-blocker.
While the ad-blockers are simple and elegant solutions, even top-tier websites, sites like Legal Insurrection and webcomics like El Goonish Shive need the ad revenue to maintain their level of quality production. (You may have noticed that I have trouble writing three articles a week. Dan Shive regularly produces 6 comics a week. That's a full-time job.)
2) Complain to the websites.
Erfworld, EGS and LI have all responded quickly to my complaints about autoplay ads and deserve credit for being on top of it. Erfworld's staff, in fact, spent roughly 120 man-hours to sort which ad networks could be trusted. Here's the problem, though: they shouldn't have to. The whole reason ad networks exist is to provide third-party support for managing ads. If a website says "No autoplay ads or redirects", that should mean no autoplay ads or redirects. The individual websites allow these ad networks to take a part of the revenue for themselves, this is part of what they are being paid for.
3) Expose the ad networks who have or continue to "accidentally" let abusive ads "slip through".
I don't believe that these ad networks are consistently missing ads with exploits or that ignore permissions. It happens too often and too frequently to be an accident. Every now and then, I could understand if an advertiser cheats a network and tricks them into displaying an abusive ad, but when the same ads consistently "break" the rules on multiple websites in the same way, I am forced to conclude that there is an understanding between the advertiser and the network.
Right now, according the Erfworld's results, the ad networks that pay the best routinely have ads that the sites have previously objected to. There needs to be an economic cost to these companies. Their reputations need to suffer.
If you run a website or can otherwise identify abusive networks, make them public. Announce them on Twitter, Facebook, your website, wherever. You can even comment below and I will construct a list. When people look for ad networks to provide some extra revenue, they'll find which networks cheat and which don't. That will make the latter more valuable, more people will host them, and more people will try to put ads on them, driving up the price of putting those ads up and therefore the revenue paid to the sites you want to support.