We'll have to wait and see how many foreign people get arrested for drinking beer or simply kissing a girl in public.
There are many strict rules in Qatar about those things, and many foreigners will probably end up doing all the "wrong things".
As strict as the rules are in Qatar, I believe that foreigners who are arrested for drinking or kissing in public are likely to have their prison sentences converted into a fine.
Obviously it won't be a cheap fine, because Qatar needs to impose that respect, but I believe that there will be this flexibility for those who are foreigners.
Of course, it all depends on the "damage" that the person commits... in the case of being absurdly drunk or parading naked through the streets, it should result in much bigger problems than a simple fine.