Skadoosh, you assume people have post-2003 door openers. Last ones I had were probably original issue withe the late 1980s construction house, and had 5 or 6 sliding pins that were each set forward or back.
Not exactly a cryptographic challenge... Not with the older stuff (that is still in some use.)
Edit: my truck has remote starting, for warming up on cold days or cooling on hot ones. But, the system kills the engine if somebody attempts to put the transmission in gear, and the remote start sequence is initiated by first pressing the door lock key.
Otherwise, I do not leave a running vehicle unattended, either.