They are running ads on the TV, saying that when the analogue TV signal gets switched off, if they haven't upgraded, then their tv set may not work properly. The key words are "may not". I think they should be saying "will not". There will be no analogue channels left, so unless they buy a STB or get a DVB capable set, then they will not get a signal. It's probably political, don't startle the proles or they may realise we're forcing them to do something that costs them money.
Any commercial that says "may not" is accurate. If you bought a TV within the past few years, chances are (at least in the US) it has a digital tuner built in. They will still work after the analog shutdown without a converter box; whether you can still pull in the same channels, however, is primarily an antenna issue. It's only people with older televisions -- purchased before the FCC practically forced manufacturers and retailers to sell TVs with digital tuners -- that need a converter box *if* they use rabbit ears.
Besides, some low-power stations in the U.S. will be permitted to transmit an analog signal past the shutoff date, so analog isn't truly going away after February.