Telemarketing success

[phone rings]

Hello, Mr West?
Yes. Hi.
Hello, I’m calling from British Gas. I believe you have an existing contract with us to service your boiler, is that right?
Yes, it is.
I’m phoning to let you know about an offer we have on at the moment which is a very good deal.
At the moment you’re paying £25 a month for your support contract, I believe?
Yes, that’s right.
Our new offer would add electricity and drainage cover to your contract for an extra 25p per month
Um, I don’t think I really…wait, 25 pence, not pounds?
Yes, it’s a very good offer.
[beat] How long would this last?
Twelve months, after which it will go up to an extra £9.75 per month. I can add it right away, and send you the paperwork with a seven-day cooling off period so you can check all the details. Would you like to go ahead?
Um. It really covers all the wiring in the flat?
…Ok, then.

I don’t think I’ve ever said yes to a phone call like this before. The trick here is that they’re hoping I won’t revert back to the cheaper contract once a year has passed, right? I’m not missing anything, am I?