I'm not sure how easy it would be to implement, but we are training the Youth members of the church in the use of OpenLP, so it would be handy if could have a Administrator and a User level so that anything only the Administrator can make any changes that affect the database.
you could probably achieve this relatively easily with different
read/write permissions to OpenLP data folder set for your
computers User Accounts. (Admin + normal user for example)
2) Install OpenLP on that second machine
3) Point that new install of OpenLP to the folder where you put the files
4) Voila! One new training machine
OR (slightly more arduous, but requires no new hardware)
1) Copy the folder with all of OpenLP's settings files to another folder
2) When you use the PC for training tell OpenLP to look at that second folder
3) When you use the PC for presentations tell OpenLP to look at the normal folder
OR (simpler, and no new hardware, and extra features)
1) Copy the folder with all of OpenLP's settings files to DropBox or OneDrive
2) Redirect OpenLP to look at that new folder
3) If one of your youth messes up the database, use the file history on DropBox or OneDrive to go back a previous version of the database.
BONUS FEATURE: This option, which I use, enables you to have the same database across various PCs. Although I wouldn't do it if you wanted to use both machines simultaneously, and you do have to allow a couple of minutes for changes to sync each time you boot the PC.