Flyer receives frequent flyer mileage credits in the following situations. Should Flyer have gross income?

(a) Flyer recieves the mileage credits as a part of a purchase of ticket for a personal trip. The credits are assignable.

(b) Flyer receives credits from Employer for business flight Flyer takes for Employer. The credits are assignable.

(c) Flyer recieves the credits under the circumstances of (b), above, but they are nonassignable.

(d) Same as (c), above, except Flyer uses the nonassignable Employer-provided credits to take the trip.

(e) Flyer opens a bank account, receives 50,000 "thank you points" from Bank, and redeems the points for a flight valued at $650.