I think it is not possible, as their bonus terms requires to make at least one deposit after you complete other requirements (rollover)
I have asked this via pm a week ago when I won the first week giveaway, and they said the you need 30x rollover.
At least players need to know whether they have completed the rollover or not. But I cant find any menu to see how many rollover I have made, perhaps we need to ask live support about it. Another thing to know is that about the minimum deposit..
P.S : Need official statements regarding the third question, so lets see and wait for OP answer it.
Thank you for clarifying Panjul!!
1. It's possible to withdraw without making a deposit as long as you have completed the rollover requirements
2. Rollover requirements are 30 times for most bonuses unless specified otherwise.
3. The only thing they need to know before attempting a withdrawal is their rollover, dont be shy, come to the chat and we will let you know exactly where you are standing and just so you have an idea of the rollover contribution of the games check the table of percentages here http://4grinz.com/bonus-terms
Thanks for the reply and information! I will be visiting your site again soon!