If they have a dremel, those can really be nice for slotting -- I've futzed with punches, saddle valves,..., and a rotary tool with tube cutter head is both easy and consistent.
Then again, I do use the dremel for other things, paid for itself when I needed to route a cutout in a switch I was replacing on a stove. Cost me $10 for a generic switch instead of almost $100 for OEM.
A Dremel is like an electric swiss army knife... I don't have a legitimate use for half the tips, but I constantly find myself thinking I wonder if I could use the Dremel for this...