pixel shader support - can you fake it?

2 questions really.

Splinter cell 2 won't play on a GF4MX because of the lack of pixel shader
support. Says so on the box, says so in the "test your machine". My
neighbour really wanted to play this game so I swapped him my 9800PRO for
his GF4MX440SE. I thought I would just see what happens if I load spinter
cell 2. Loads the menu and when you try to start the game it quits to the
desktop. Oh well, I thought, never hurt to try. Then I loaded it again
and loaded one of my saved games and it worked. More experimenting shows I
can load every level except level 1!. Some of them look damn shocking and
would just be impossible to play. Some others you wouldn't know the
difference.
So my first question is can you fake pixel shader support to play the game
and just not have it show whatever pixel shaders do?

My second question is how hard would it have been to write in to simply not
show pixel shader effects? So the game would still play on lower cards but
wouldn't look as good? Or is the pixel shader code so tidied into
everything else it would have been a mission to have some kinda of
subroutine to bypass it? Or do they just expect that everyone who wants to
play the game will have or buy a flasher video card?

I also notice after clocking the game (actually noticed well before that but
thought I'd throw the fact that I clocked the game in there for an ego trip)
that it really resembles SC 1 in the graphics and gameplay department.
Everything looks sharper and cleaner and the physics are definitely better
but if you played SC 1 for a level and SC 2 for a level you really would
have trouble ID'ing the 2. And SC1 run on a GeForce 1.
Also I got Beyond good and evil which is my most recommended game of all
time. It is simply amazing. I mention this because the general opinion of
this household is the graphics in BGAE are WAY better than SC2. And BGAE
will play on the lower cards without pixel shader support AND both games are
made by the same company (UBISOFT)

Thoughts?