Cordless Phone Interception?

I recently began recieving cordless phone transmissions on my Jensen wireless stereo headphones. The reciever is on 900MHz, but the phones are supposed to be on 2.4 GHz.
I wonder if it's possible that someone in my neighborhood is using some sort of relay system which recieves & converts all three common phone frequencies and re-transmits them on 900MHz. (?)

 

Well...that still doesn't explain why I would be recieving transmissions from my own 2.4 GHz phones on a 900MHz reciever. Something must be converting the signal.

 

I may have figured it out. Apparently, many of the 2.4GHz phones also use 900MHz -tho, they don't say so in any of the packaging or manuals. One frequency is used for base to handset, and another for handset to base.Personally, I find that deceptive. Especially since that defeats the reason why I bought the 2.4 instead of the cheaper 900. The DSS systems may improve privacy, but according to many reviews, may not be as strong or consistant in terms of reception. Only trial use can tell.The company that made my phones, Uniden now uses "true" or the same frequencies for send and recieve in their newer models.This is indicated in their model names with the prefix "TRU"xxxx. My system is only 3 years old. For now, I'm using a cell phone and corded phones( thrift store - $3 each).
It's not a big issue for me, now that -I think I know- what is going on. But, people need to be aware. I overheard one neighbor entering a security pin-code while placing an order. This is never advisable. People do it anyway. How long till I hear something -I REALLY WISH I HADN'T?
Here is an article I found helpful:
Epinions.com - 900MHz vs. 2.4GHz vs. 5.8GHz
And by the way, thank you for the responses.