+1 holding bikes doesn't pay.
The last time I went to visit my in-laws out of State I brought a project bike with me in the car. Restored the bike in my wife's parents garage the first couple days I was there and decided to put it up on the local Craigslist to see if I could make a little profit. A guy called pretty much right away, asked a few question and say's he wants it, consider it sold. But he's out of town and won't be back until the day before I am leaving (it was the holiday's everybody is traveling). Ok, I agree to hold it, partly because that would give me something to ride on my vacation and partly because I am always glad to sell to somebody who will appreciate the work I put into a bike and he seemed excited about it. Long story short, he contacted me several times through out the week reassuring me he wanted it and I believed him. I turned away several other potential buyers, he didn't come through, never showed up and didn't return my call the day before I was leaving. I didn't have room in the car for the bike as my family had accumulated a bunch of stuff and I had to leave the bike, eventually my wife's parents came to visit and brought it with them but it was big hassle, all because I was trying to do a stranger a favor.
That said I have told a couple sellers to consider bikes sold, and I make darn sure that if give my word on that, I'm buying the bike. The only way I would go back on my word is if I arrived and found the frame to be cracked or found out that the buyer had substantially deceived me in some way.