Merchants in the travel category include airlines, hotels, motels, timeshares, car rental agencies, cruise lines, travel agencies, discount travel sites, campgrounds and operators of passenger trains, buses, taxis, limousines, ferries, toll bridges and highways, and parking lots and garages.
Please note that some merchants that provide transportation and travel-related services are not included in this category; for example, real estate agents, in-flight goods and services, on-board cruise line goods and services, sightseeing activities, excursions, tourist attractions, merchants within hotels and airports, and merchants that rent vehicles for the purpose of hauling. In addition, the purchasing of points or miles does not qualify in this category.
Thanks for the quick reply. With some searching on Flyertalk it turns out that if you get a refund for a travel expense, the credit doesn't go away. So I just booked a refundable stay on Expedia to trigger it and will cancel it after it posts. Caution: MAKE SURE that the hotel doesn't charge a cancellation fee, as Expedia will pass that along off of the refund.