Before I start my work with PIC I was use HC11 ... all time I didn't use standard security (protect my design) usually I didn't only protect code I protect design with some extra electronics on my design like:
MICROWIREвт Bus Interface 256-Bit Serial EEPROM with Data Protect and Sequential Read (FM93CS06)
about thief ... many alarm systems use PIC ... and electrical pulse is not problem because its dependent on your peripherals connection on pic. All alarms or locker on input, output and bus have some kind of (Isolated) protection like
2.0 Amp IGBT Gate Drive Optocoupler with Integrated Over-current Protection and Fault Feedback (HCPL-3160),
+5V Powered Isolated RS-232 Drivers/Receivers (MAX251),
Isolated Single Output ( RZ-1515S ).....
its dependent on your project what you need, what you wont and of price which you anticipate for project cost ....