[barisme]

Yes or 'they' might use a form of energy that is totally foreign to us. Maybe it's not even a beam or a ray. Maybe it's micro-black-hole-oscillation (yeah, made that up). I mean, who knows? It's all hypothetical anyway. And here we are spending money on a bunch of dishes that pick up a specific range of radio frequency. Stick the same dishes on top of a sports bar and at least we can all watch football.

[iwwr]

The advantage of SETI is that the radio equipment can be used for radio astronomy just as well. So the money spent has dual use (almost complementary).