Don't know about specific local laws, but where I live, even outside the probationary period you can be let go with no reason given. It's an At Will Employment.
I just finished a 30-day trial consulting contract at my new job. For all intents and purposes I was fully hired, however certain paperwork was pending the trial period as a business caution. Today was officially my second day of actual full-time employment, although I've been earning my salary for the past month. Even still, my next 90-days are still considered probationary per my employment agreement, although I also have in writing that my current employment is not a trial any longer.
All that is to say, try not to sweat it, because that will only make you hate what you're doing. If you get it, and it's what you want, jump in and do your best. I'm sure it will work out. The company wouldn't be able to survive if they just dumped any and all new talent simply on whims.