Not really. As the consumer, you don't pay $30 for a stock that's trading at $20. What you are referring to is when a company pays over the enterprise value for another company. This does regularly happen, since synergies can sometimes justify this.

For the purpose of miles and points, my "quick" rules are:

1. Always get over 2% in value from spend, since that is the baseline
2. Never value your points or miles at an amount greater than you can buy them at.
3. When redeeming, always calculate the NET cost/mile.

For instance, let's say you redeem 50,000 miles for a $1,000 trip that is 10,000 miles away. Most people would say "Oh I got $0.02 cents per miles ($1,000/50,000). However, you must take the forgone miles you would have earned, into your redemption. In this example you forgone 10,000 miles by redeeming an award.

You basically "spent" 60,000 miles instead of 50,000. This example also does not include elite status, which further supports reason 3.