I wouldn't ever consider taking a taxi without the carseat, as Aquarian said the injuries sustained to your baby would be horrific in a crash. In a car crash (even a minor one) your head 'whiplashes', when you are wearing your baby in a sling or carrier their head is on your chest, you would very likely kill your baby with the downward force of your head. When I think about this, having to take the bus or struggle with a stroller isn't really an issue.