In theory, they could ask for both evidence of an exit and proof of funds, but I have never been asked for that. If you are from a country that is eligible for visa-on-arrival/no visa, then I seriously doubt that they would check.

One workaround is if you have a travel agent who can book you an official-looking itinerary to show (even before purchasing it), then that should work. Or, of course, you could buy a refundable return one-way ticket and get a refund once you're in Europe.

As for the proof of funds, showing them a credit card should work. Again they could dig deeper, but I seriously doubt that they would.

I would be curious to hear if anyone has actually had the experience of having to produce these documents in Europe.