Falling asleep in the car seat: Blessing or Curse?

I'm not sure how much I like Jacob falling asleep in the car seat. Usually it is a great gift for us, but consider what has happened this week.

Wednesday morning, Jacob and I went to play date at Elana's up in Woodstock, Maryland, about half an hour away. We left a little before 9 so we could get there for 9:30. About 9:20, Jacob gave in and fell asleep in his car seat, as he often does. I wondered what to do, because we were just about there and I didn't want to bail out on the play date at the last minute. So I parked in the driveway, got stuff together to take inside and finally bit the bullet and took Jacob out of his car seat. He showed some signs of waking up. After we got inside he started to perk up quite a bit. By the time Elana served yummy pumpkin muffins, Jacob was in full play mode. Having a ten to fifteen minute nap seems to have done him well, because he stayed awake and was chipper the whole time (except when he overflowed his diaper and needed to change everything). We even left without any big conflicts/blow ups with any of the children. It was a great play date.

On the way home, he resisted falling asleep until the very last minute, which was harrowing for me. He didn't quite make it to his bed asleep, so I had to sing him back into sleepiness. I find that singing the same song over and over and over and over helps bore him back to sleep. Luckily, my tolerance for boredom is higher than his.

Today, we were going to the library for story time to be followed by the grocery story for shopping time. We left at 9:40. The library is only ten or fifteen minutes away. Five minutes into the trip, he was out like a broken light bulb. What to do? Should I stay the course and wake him up at the library with another 15 minute nap? Since the babysitter is coming today for her 3 p.m. to 5 p.m. gig, I thought it best to let him continue to sleep in the morning, rather than wake him and have him fall asleep at 12:30 and sleep through the time that the babysitter is here. I hope I made the right choice.

Why has car seat napping become so fraught with peril?