Assuming you mean, other than the ethical concerns?
A) Who's insuring the ride? If it's not insured and the driver is at fault in a collision, there could be no one to pay for injuries to you -- Lyft/Uber certainly wouldn't owe anything for stuff booked outside their platform.
Usually when they drive for a TNC, the TNC provides the insurance for the driver in the course of using the app. It's really unlikely for the driver to have a policy that covers them for non-TNC freelance rides -- especially since the big insurers haven't caught up to the realities of this use case and seriously overprice them.
(AIUI, they just have policies that assume you drive full time commercially, nothing that works on a per mile basis -- and even if they do have such policies, that would defeat most of the purpose of cutting out middlemen, as there would now be a written record of the transaction that can't be hidden on taxes.)
B) In order to get enough information to re-book out-of-band you'd have to accept it and then cancel. Do that a lot and it will be grounds for being kicked off the platform.
(The same applies to the people in the anecdotes in the sibling comments.)
A) Who's insuring the ride? If it's not insured and the driver is at fault in a collision, there could be no one to pay for injuries to you -- Lyft/Uber certainly wouldn't owe anything for stuff booked outside their platform.
Usually when they drive for a TNC, the TNC provides the insurance for the driver in the course of using the app. It's really unlikely for the driver to have a policy that covers them for non-TNC freelance rides -- especially since the big insurers haven't caught up to the realities of this use case and seriously overprice them.
(AIUI, they just have policies that assume you drive full time commercially, nothing that works on a per mile basis -- and even if they do have such policies, that would defeat most of the purpose of cutting out middlemen, as there would now be a written record of the transaction that can't be hidden on taxes.)
B) In order to get enough information to re-book out-of-band you'd have to accept it and then cancel. Do that a lot and it will be grounds for being kicked off the platform.
(The same applies to the people in the anecdotes in the sibling comments.)