SINGAPORE - What are the chances of getting a highly sought-after random reward from a virtual goody bag in an Apple App Store mobile game?

A check of 10 games by The Straits Times showed that it can be lower than 1 per cent, with one popular game citing a chance of 0.00005 per cent.

Some observers are concerned because they contend many of these goody bags, also called loot boxes, have addictive gambling-like qualities and can be bought or opened with real cash or virtual currency bought with hard cash.

Game developers were forced to reveal the odds of getting loot box prizes in games from the App Store after iPhone maker Apple made it a requirement last December.

While it took a while, many developers have since complied. Several revealed the odds earlier due to a similar requirement in China in March last year.

Previously, gamers were left in the dark or would figure out the odds themselves.

How their rewards' odds are disclosed varies from game to game.

Some games reveal the odds of individual rewards, while some only show the chance to win an item from a category of rewards.

For instance, popular multiplayer online battle arena game Vainglory cites a 0.00005 per cent chance to win one million Ice, which is a premium currency in the game.

But in Clash Royale, which has elements of a collectible card game, the chance to get a card from a category of several cards dubbed "legendary" is 0.19 per cent. The chance for a specific legendary card is not officially revealed and could be lower.

Rare loot box rewards can give players a big advantage in some games, while in others they are just for show.

The odds in some games can change under certain conditions too. In role-playing game Mobius Final Fantasy, there are special events that increase the odds of getting a supreme card by 10 times to 0.8 per cent.

In Clash Royale, the drop rate for a legendary card jumps to 100 per cent when opening a special type of loot box, which can be harder to get.

Even so, these odds - with the exception of Vainglory - are generally higher than the 0.0002 per cent chance of getting a royal flush in the poker card game.

Apple's move to reveal the loot box odds in games follows an outcry late last year by gamers over the gambling-like features of the loot boxes in shooter game Star Wars Battlefront II, which prompted investigations in countries such as Belgium, France and the Netherlands.

Google was unable to confirm that such measures as the ones Apple made would be implemented for its Play mobile store.

Mr Jonathan Kok, a partner at RHT LawTaylor Wessing who practices law in media and entertainment, said that there are no reports of Apple actually terminating a game developer's participation for failing to disclose the odds of receiving each type of item to customers prior to purchase.

But he said that if Apple discovers a violation, "it is likely that Apple will notify the developer of the breach and require the developer to address the breach within 30 days".

Failing which, Mr Kok said Apple would remove the offending app from the App Store.

Mr Shawn Toh, chief executive of BattleBrew Productions, a local game developer, said revealing loot box numbers is useful.

"Regular players should get to know the odds, especially if they are willing to spend their own money to get a specific item. This makes it clear for players to decide if they want to take the chance and get what they want, provided that the odds are fair, of course," he said.

Other experts were uncertain that informing gamers of loot box odds would help.

Dr Thomas Lee, consultant psychiatrist and medical director of Resilienz Singapore, said: "Gambling operators - like in horse racing or Toto - also advise patrons on the odds of which they will win. But some of these patrons still find themselves addicted to gambling, even when they know that the odds are stacked against them.

"These odds help you to make a better decision, but it is up to the individual to decide whether he wants to take that chance. Unfortunately for some, they end up in addiction."

Mr Allan Simonsen, chairman of the International Game Developers Association for Singapore, said some users are susceptible to a "feel good" high from getting loot box rewards, adding: "They're not going to be looking at a probability table to decide whether they want to open the box or not."