I think you are quite brave going for a dry loop. This isn't something widely available yet here, but it could be just around the corner.

In the UK I wouldn't recommend that to anyone, retain dial tone on your line. I know the state of our network in the UK inside out, and with pairs at a premium the last thing you want is to not have dial tone. Before you know it "someone" will pinch it away as engineering techniques in general haven't moved on for 50 years and most don't think to check for a digital signal before assuming it's a spare.

Of course this is against company policy, but what would you do yourself? I bet a high percentage wouldn't be following the company line!

I hope practices in Canada are a little more advanced than here.

Cheers

Cris.