What is the purpose of resistance & capacitance in parallel to Load ( refer ckt )
Each of the LED's with have a voltage drop across them (depending upon color) from 6 - 12 Volts. since there is a stack of three of them.  Therefore the residual voltage with low or zero current draw will be on the same size/magnitude.  This means that the voltage across the LED's won't collapse quickly below this voltage when power is removed.

The shunt resistor in front of the diode is a bleed resistor, it is meant to bleed off charge from the de-rippling capacitors in the event of a power down.  This prevent the capacitors from providing a voltage (back feed) to the +12V input when powered down.

These voltages are not dangerous to humans, it's more of a circuit protection scheme.