Hi,
Current-limiting may indeed give some useful protection to the overall system, but note that the LTC4362 (and most others) is intended to protect the downstream electronics (e.g. the PICaxe) from overvoltage/current, whilst the issue raised by the OP and particularly in post #4 is the protection of the upstream electronics, i.e. the PC/Laptop/USB ports.
Unfortunately series semiconductor switches or transistors may not, (and sometimes cannot) isolate the reverse flow of current, back into the source and thus may not protect against damage. For example many FETs and ic transistors have an integral reverse diode connected between their "output" and "input" terminals (either intentionally or as a "parasitic") which might, or might not, be shown on their schematic symbol.
Bench power supplies, and other high reliability systems often include "shunt" protection in the form of a triggered SCR/Thyristor (sometimes called a "Crowbar") or a Zener diode to ground, to "dump" any excess voltage (from wherever it might originate). Generally, under severe overload conditions SCRs and Zeners are considered to "fail safe" (i.e. to a short circuit) whilst the bond wires in integrated circuits can blow open circuit, (like a fuse) and cease to protect the system.
Cheers, Alan..