True, you're not going to get this extreme level of access to the machine. But even doing things like ssh'ing in to many machines to use it as a personal distributed cluster, even if you did everything to make your program run at the lowest reasonable priority, got some people in trouble at one university I was at.

Is gp mentions SSH, that means software is not running in real mode.

And if you can get SSH, chances are sooner or later you can exploit some misconfiguration or something else to escalate to root.

Years ago having send mail installed basically meant having a security hole... And sendmail was very common.