Advice, wiring switched and constant power wires together ..

Hi,
I've got a new Kenwood stereo/cd player deck for a '90 Golf. The deck
is pretty basic, nothing fancy (KDC-1028).

Several folks in this group suggested using the key-in-ignition line
(SU contact, 12V when key is inserted) to operate a relay, the relay
then supplies switched power to the radio's yellow wire.

I'm wondering if I can wire the constant power and switched power wires
together. The Kenwood deck has a power switch and when pressed, the
deck display goes off and it appears the deck pretty much powers down.
I called Kenwood Canada and they confirmed that with the deck in
power-off mode, it's only drawing power to keep the memory and clock
alive.

The Kenwood radio would operate much like the stock VW radio did. The
VW radio turned on without any key in the iginition. The VW radio also
drew some power to keep the station memory and clock alive.

As for leaving the radio on, after 20 years with an A1 and A2, it's 2nd
nature to check that the radio is off, along with checking that the
windows were closed, trunk locked, passenger door locked, valuables out
of sight....when parking. The display on the Kenwood is much brighter
than the tiny LCD on the VW radio, so it shouldn't be hard seeing that
it needs to be turned off.

Soooo....I'm considering installing with constant power to both the red
and yellow wires.

Any advice to the contrary? Any downsides to having the new radio
operate just like the old?

Thanks.
-Tony

(How this all started. Wife's '85 Golf odometer stopped working. Take
dash apart, repair odometer. Hey, why not swap out the 20 yr old radio
from the '85 and replace with "newer" 15 year old radio from the '90.
Then get new radio with CD player for the '90).