As video games — playing them and watching other people play them — have exploded into a multibillion-dollar form of mainstream entertainment, the money, naturally, has followed. In addition to the big business of making and promoting video games, a small but growing number of players are establishing lucrative careers by streaming themselves playing games on sites like Twitch, and/or uploading video of those play sessions on YouTube.

It shouldn’t surprise anyone, then, that some ethical issues have arisen around all that money. For a really good example, take what’s going on with the website CSGO Lotto.

Here are the basics: Trevor “TmarTn’’ Martin and Tom “Syndicate’’ Cassell are two very popular YouTube personalities, with millions of followers each on that site (they’re also on Twitch, though a glance at their pages suggests they haven’t streamed much there lately). Both are charismatic and have built their followings by playing a bunch of games in an entertaining way, and both are fans of “Counter-Strike: Global Offensive,’’ an uber-popular tactical first-person shooter.

Martin and Cassell have published a number of YouTube videos that involve them playing around on CSGO Lotto, a website that allows “CounterStrike’’ players to gamble weapon skins they find in the game (that is, items that give weapons distinctive appearances) for a chance to win real money — a somewhat shady activity that circumvents laws against Internet gambling, and which kids as young as 13 (the site’s age limit) are participating in, helping the companies that run such operations to profit immensely. The Martin and Cassell videos gave the impression that they had either discovered the site on their own or were being sponsored by it.

Except, nope. It turns out Martin and Cassell are co-owners of the site, meaning they profit when people sign up for it. They never disclosed that fact — in a video from March, Martin even said he had “found a new site,’’ referencing CSGO Lotto in an extremely misleading way.

We know about their involvement thanks to another pair of YouTubers, Ethan “h3h3Productions’’ Klein and HonorTheCall, who released a deeply researched video on July 3 which looked into CSGO Lotto’s incorporation papers and searched, to no avail, for evidence that either Martin or Cassell had ever disclosed their stakes in the site. The video exploded into a blockbuster story, earning writeups in gaming and gaming-adjacent sites ranging from Ars Technica to Polygon and even ESPN, which eventually roped in a third streamer, Josh “JoshOG’’ Beaver. ESPN reported that “Martin currently acts as the company’s president, Cassell as vice president, and Beaver as secretary.’’

Maybe this will serve as an important milestone for streamers and YouTube personalities in general — entertainers for whom the professional norms already firmly in place for journalists, actors, and other people susceptible to this sort of conflict of interest are still a bit nascent and fuzzy.

The backlash against this sleazy behavior has been encouraging: Everyone in the gaming community agrees this is wrong, and the whole story blew up in the first place because of other YouTube personalities. Maybe streaming is in an awkward adolescence, but an incident like this could help nudge it forward. Either way, it’s a reminder of just how messy things inevitably get when art collides with truckloads of money for the first time.

Jesse Singal can be reached at jesse.r.singal@gmail.com.