Hard to log an ILS approach if the plane doesn't have a GS.

Nonsense. I just have the safety pilot point one of his fingers
horizontally on one hand and vertically on the other. Then, while crossing
the fingers and putting them in view of the PIC (with a V.L.D. on, of
course), the safety pilot can look outside and estimate the glideslope.
It's also critical that the S.P. have a good voice range, as emulation of
the marker beacons can be difficult otherwise. It should be noted that beef
jerky sticks can substitute fingers, but equipment function is more likely
if pilot hunger is moderate.

If you want to simulate intercepting a GS too high and receiving an
incorrect angle, have the S.P. consume any alcoholic beverage(s) and/or nail
polish remover. If unwilling, tell him/her that he needs to identify the
100LL with a good sniff, as "fuel gnomes" have been known to steal gas and
replace it with blue water. This should result in faulty "instrumentation."

Sorry, it's late...had to do it...

Justin