I am still new at this so I am learning something everyday. The R-sec mines can be placed in very specific places, last night I stuck them in different places on the razorback tires. I don't know if it useful but it sure looks cool.
It's best to put a R-sec on the sidewinder or hawk. It's very dangerous to put a R-sec on a tank, RB, or grizzly. If you put one one a RB, tank or grizzly, you need to jump out if you run over someone.
More advice: if you enter an enemy bunker, base, zone, or flag area, always listen for the R-secs beeping sound.
To get the most out of a R-sec on a razzorback, ram the RB into a bunker full of enemies and jump out.
Huge Freespace fan here!
I wish this game had more elements of Freespace 1 & 2 and a hint more of Battlezone RTS/FPS to it, but it's for the common shooter crowd. We can't have everything.