So, this seems like a really important place to be clear about language because you've mentioned shuttles and taxis. The law says that personal cars have one particular system - a child restraint for any child under 5. Buses (for schools, cities, and for hire - which would include shuttles) are exempt from this (law doesn't state why but without seatbelts, many/most buses would have a hard time integrating restraints -
kudos to Sunshine Flyer for being mindful of this!).
The
law states that it's the parent/guardian's responsibility to provide a child seat - not the taxi/shuttle/etc (if for hire). So, all the last part does is let companies off the hook of providing it and it places that responsibility on parents/guardians. At
no point does the Florida law say that kids under 5 can be without a restraint system in a car.
On the families board and/or transportation boards, there are threads about this sort of issue - some people have reported that some taxi drivers (since you wrote that specifically) may drive without a car seat but they (the parents) felt uncomfortable, since the law states that kids under 5 need a car seat. Some have reported taxi drivers won't drive without a car seat at all. In terms of both safety and legal ramifications, if you plan to rent a car, use a taxi, or use a rideshare app - you need a restraint system for any child under 5. If you are only using buses, this statute doesn't require a restraint system and families tend to not use one.
I'm by no means a legal professional or transportation guru - I just was really interested in the post about this program (the new Sunshine Flyer one, if you lost the thread getting to this post, lol) and happen to have been looking at these weighing my options for my own trip. I have feelings about what I think people should do but am trying not to let that into this conversation (so I'm actually going to check out and let others weigh in).