Why does SPI_connect change the memory context?

SPI_connect() changes the memory context to a newly-created one, and
then SPI_finish() restores it. That seems a bit dangerous because the
caller might not be expecting it. Is there a reason it doesn't just
change to the new memory context as-needed?

spi.c:161:

   /* ... and switch to procedure's context */
    _SPI_current->savedcxt = MemoryContextSwitchTo(_SPI_current-
>procCxt);

Regards,
    Jeff Davis