Good question. Many of my test cases involved mixing in text, when I eventually realized that the presence of text has nothing to do with it.
But I just made the following example (by stealing the Underdelve code from Even Weirder Worlds):
If I answer yes, or I answer no, the result is the same. Crash to desktop.
BTW... this code is generic enough that it can be placed into any mod, if you want to try it out.
I removed all my custom images and OGG files and what not.
Code:
FLAG always
KEYS unstablestar5
STAR 0
NOFL binary1 binary2 blhole
STRN Omni
FLAG nearby
END STAR
CONDITION 0
TYPE explore
STR0 0
END CONDITION
PAGE 0
REQ0 0
DISP 1
ACTN popup
GFXP misc/nova.jpg
MUSC misc/nova_loop.ogg
TITL Alien Probe
TEXT Your crew encounters an alien probe of unknown...
YSNO 1 2
END PAGE
PAGE 1
NOVA 0 5 5 exo_neutron devastated
ACTN popup endquest
TITL Play it Safe
GFXP misc/nova.jpg
TEXT You decide not to risk the lives of your crew...
MUSC misc/nova_loop.ogg
SCOR 100 exploring
SVAR udcrew neverwent
ACTN endquest
END PAGE
PAGE 2
ACTN popup endquest
TITL Play it Safe
GFXP misc/nova.jpg
TEXT You decide not to risk the lives of your crew...
MUSC misc/nova_loop.ogg
SCOR 100 exploring
SVAR udcrew neverwent
ACTN endquest
NOVA 0 5 5 exo_neutron devastated
END PAGE