<font face="Verdana, Arial, Helvetica, sans-serif" size="2">Originally posted by Spiff:
Re: Delta Vacations:
"We welcome solo travelers. Please note, however, that all package prices quoted on previous pages are per person, based on double occupancy (2 people).
If you are a single traveler, there will be a price increase (in effect, a “single supplement”) at check-out, because you are not sharing the cost of a hotel room and/or rental car with a second traveler."

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Yeah, that's the other drawback. It's not much of an issue for HRGM and I for obvious reasons
Of course, if you did need a hotel and/or car at your destination, you'd still be paying for it and unable to spread the cost over two or more people. (Since most hotel rates are the same or very close for 1 or 2 people, you wouldn't save much by getting a single room.)
I would compare the price for the total package with what you would have spent on separate air & ground arrangements. If you would usually stay in a Super 8 or use a cheap Priceline hotel, that may tend to push you away from the Delta Vacations deals; if you'd take a more expensive hotel, the package may be cheaper overall even with single occupancy.