If the installer goes past partitioning, and it does not have a swap partition. couldn't It warn them before proceeding that sleep and suspend* will not be available?
It saves the headache of having to set it up later if you want to use these features, and also lets them know that if they go that route what is going to happen if they try. Personally I do not know of any installer that does this, but it seems like the nice thing to do.
* I know suspend to ram would still work, but that leaves folks with a false sense of security because if the battery runs low it tries to write it out to swap, fails, shuts down and turns back on into a mess. It is almost worse IMHO.