This right here.........if I was the one picking her up and/or in charge of her coming to and event, she would have gotten left at the airport and told that she can go back home. And when people asked why she did not speak at the event, I would have told the ENTIRE truth. If they had an issue with this person not appearing after the explanation, they can go home too. Because a certain person delivering the word does not make it that much more valid than a "no-name" messenger.
I present a different perspective on this, though I don't disagree with the sentiment behind yours.
First of all, this should've been ironed out in advance. When a church is booking a speaker to come to their church, SOMEONE (administrator, pastor, secretary, associate minister, etc.) is responsible for communicating with the speaker and/or his representative. We have a form that I send out to all guests asking them what their needs, preferences, and requirements are as it relates to travel, ground transportation, hotel accommodations, meals, and honoraria. If they don't send the form back, I will e-mail and call until I get answers. I at least like to know what they want to eat/drink and if they have any other must-have requirements.
So I would've known in advance that this speaker expected to be picked up in a specific car. Chances are, this speaker wouldn't be booked at my church because my pastor doesn't play that and neither do I. But let's just say s/he did get booked...
I would first pull out her accommodation form to see if she specified that requirement. If she did specify it, it is our responsibility to accommodate, since we knew in advance and booked her anyway.
If she didn't specify it, I would show her the form, explaining that she didn't make her wishes known. At that point, I would call the Pastor to tell him what my plan is and get an "okay" from him. With his approval, I would then let the speaker know that we are unable to accommodate her on such short notice and if she'd still like a ride to the hotel, I'd be glad to take her in the van. If not, I would tell her I understand, ask her if she would like me to wait while she tries to arrange for other transportation on her own, and if she declines, I'd simply wish her a safe journey back home. On the inside, I'd be hoping she declines because I wouldn't want to receive ANY KIND OF ministry from a person like that. But, as the administrator, driver, program coordinator, adjutant, or whatever, I'm not in charge and it's not my call to make.