LDO regulator with series Scottky at output?

Hello

We are using the LM2937-3.3 linear LDO voltage regulator to get 3.3V from 5V.
Output current is 50mA maximum.

LM2937-3.3 DATASHEET:
**broken link removed**

The previous engineer has placed a series Schottky diode (D12) following the LM2937 (i.e, the Schottky is immediately upstream of the output cap as in following diagram)

CIRCUIT DIAGRAM:
http://i54.tinypic.com/a2py7k.jpg

…..the load has been represented as a resistor, but actually it’s a MC13211 RF Transceiver which has a 2V to 3.4V operating voltage with on-chip voltage regulators….(3.6V max recommended input voltage as per page 46 of the datasheet)

MC13211 DATASHEET:
http://cache.freescale.com/files/rf_if/doc/data_sheet/MC1321x.pdf?pspll=1


Anyway,
I am wondering why the previous engineer added the series Schottky diode?

I noticed nothing about putting a Schottky at the output in the datasheet.

I am wondering perhaps , is it a problem if the input side is at zero volts and yet the output has some hold-up voltage lingering on the output caps.?

Or, do you know why a Scottky (D12) would be placed here?

I think previous engineer wants to obtain 3v from that regulator, and don't have available a 3V regulator. Or, maybe it wants to prevent reverse spikes from load. I don't see any other reason, it's not necessary.