This more a function of how your system is setup. Remastersys makes no changes to your installed system other than adding casper adn ubiquity which are required for the live to work and be installable. Casper does all setup of the live system including mounting swap partitions if found.
I have always been of the school of thought that remastersys should not make major changes to the system and leaves that up to you instead. There are arguments for both sides of this issue and I don't think an app to backup your system should really dictate how you use your system.
You can set these things in /etc/sysctl.conf and for more info on it you can see this page - http://unixfoo.blogspot.ca/2007/11/linux-performance-tuning.html