I guarantee it will continue to work. What's strange though, is that I have my modem and router set up in my living room, and my cordless telephone only sits about 5 or 6 feet away, yet I haven't experienced any disconnection problems (certainly not on the scale of what you went through).
Of course, they have different types of cordless phones, and different types may cause different amounts and types of interference. Some operate on the 900mhz band, some operate at 1Ghz or more, and then there's those spectrum spread telephones. So I guess it could all depend on exactly what kind of cordless phones you have.