Hoe kun je eerlijk een verloting doen op Facebook?

Ik wil de mensen die 'liken' allemaal evenveel kans geven, dus random iemand trekken uit het lijstje met likers. Hoe doe je dat?

Deel en win acties mogen helemaal niet volgens de facebook richtlijnen: https://www.facebook.com/page_guidelines.php#promotionsguidelines

If you use Facebook to communicate about or administer a promotion (such as a contest or sweepstakes), you are responsible for the lawful operation of that promotion, including the official rules, offer terms and eligibility requirements (e.g., age and residency restrictions), and compliance with regulations governing the promotion and all prizes offered in connection with the promotion (e.g., registration and obtaining necessary regulatory approvals). Please note that compliance with these guidelines does not constitute the lawfulness of a promotion. Promotions are subject to many regulations and if you are not certain that your promotion complies with applicable law, please consult with an expert.
i. Promotions on Facebook must be administered within Apps on Facebook.com, either on a Canvas Page or a Page App.
ii. Promotions on Facebook must include the following:
a. A complete release of Facebook by each entrant or participant.
b. Acknowledgment that the promotion is in no way sponsored, endorsed or administered by, or associated with, Facebook.
c. Disclosure that the participant is providing information to [disclose recipient(s) of information] and not to Facebook.
iii. You must not condition registration or entry upon the user taking any action using any Facebook features or functionality other than liking a Page, checking in to a Place, or connecting to your app. For example, you must not condition registration or entry upon the user liking a Wall post, or commenting or uploading a photo on a Wall.
iv. You must not use Facebook features or functionality as a promotion’s registration or entry mechanism. For example, the act of liking a Page or checking in to a Place cannot automatically register or enter a promotion participant.
v. You must not use Facebook features or functionality, such as the Like button, as a voting mechanism for a promotion.
vi. You must not notify winners through Facebook, such as through Facebook messages, chat, or posts on profiles (timelines) or Pages.
vii. Definitions:
a. By “administration” we mean the operation of any element of the promotion, such as collecting entries, conducting a drawing, judging entries, or notifying winners.
b. By “communication” we mean promoting, advertising or referencing a promotion in any way on Facebook, e.g., in ads, on a Page, or in a Wall post.

Jeetje Ritsuka, dat wist ik helemaal niet! En toch word ik om de oren geslingerd met verlotingen e.d. en heb ik al geregeld een leuk boek, een poster of een T-shirt gekregen bij een verloting.

Maar hoe kies ik dan de liker die wint? Eerste balnummer van boven op alfabet of zo?