There is no way to gamble safely that is why it is called gambling you pay your money or bitcoin in this case you take your chances, sometimes you win most times you lose...
There's skill involved in many of these games, and yes, it's true - you can't discount luck.
Still, if you're going to gamble in the first place, you should trust and feel comfortable with the site you're playing on.
I'm not sure if the legal / jurisdictional points that Andrew made in his article are all that relevant yet, except perhaps for Sport Betting (a whole different beast), but once Bitcoin based gambling gains a larger market, it's possible that there could be (distant future) a time when some US and UK based sites get shut down by authorities. Then again, Bitcoin isn't exactly money..
Still, it's a good idea for game operators to register and host in countries that allow online gambling.