Nowadays many scam casino offered a good amount or prizes to attract your attention and then when you fall into a trap scammers take all your money. So User's reviews is a must before participating in any kind of casino because every reviews from other gamblers is our way of research to determine that casino is worthy enough and trusted to gamble on their casino. But as a beginner you need to bet a small amount first in order to prevent such scam casino then if it works then you can bet a high value to earn a high amount as well.
Not even only on gambling sites, but all other sites that scammers can have a type of it. Scammers can pay many people to positively review theirbsit and they wlukdbbenlaid in order to make their site look more real to inexperienced people that can be scammed. Only reviewing the site can not do it, making more research about it would be better too and also seeking for the helpmof people about a site on forum like bitcointalk would help.