When you’ve got a Nintendo DS.  This report on Guardian Gamesblog records Nintendo Senior Managing Director Yoshihiro Mori complaining:

"DS software is not selling because users are playing the pre-installed
PictoChat game. Even if they buy a game, multiple players can use it to
play against each other, eliminating the need for each to buy their own
game…"

Hopefully however, with the right software/services in place, this would come to be seen as a strength, not a weakness of the platform.