They drill straight down for heat and only use the laser/microwave/whatever once they hit the bedrock layer. Boring conpany generally isn't going that deep and is going horizontal so possibly these techs don't apply.
Yeah, I would say using a high-energy contraption to vaporize rock (and any other stuff that might be in the way) sometimes just a few meters away from utility lines, other tunnels, people's basements etc. is generally not recommended. Plus, for geothermal drillings, the holes are much smaller than for transportation tunnels.