I'd check with a local attorney for a definitive response, since I'm only admitted in CA, but based on some quick research I found Florida Sec. 33-112. (Stopping, standing or parking between curb or edge of pavement and sidewalk or in right-of-way where posted.), which provides:
(a) No person shall stop, stand or park a vehicle:
(1) In the portion of any right-of-way between a curb or edge of pavement and the sidewalk behind such curb; or
(2) On the unpaved portion of any right-of-way, where signs are posted by authority of the traffic engineer.
While your driveway may cut across the sidewalk, I would think that, technically speaking, the sidewalk is still likely public property and blocking it could be a violation of that code section. Hope that helps.
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If a claim is brought, report the claim to your homeowner's policy, they will handle it. The kid could have used his brakes...so I'm not sure how he was "forced" into oncoming traffic by your parked car. Sounds weak....but stranger arguments have been made.
It is no type of claim that I would make, and I'm a plaintiff's attorney of course. If the child was not hurt, what is the claim? Property damage for a damaged bike? All sounds like much ado about nothing. I would do absolutely nothing unless the child's parents hire an attorney and they send you an insurance disclosure letter requesting information on your homeowners and/or automobile insurance policies. Do not get into any confrontations with the child's parents. Be polite and courteous, and my guess is this will all be soon forgotten. Good luck.