I will always provide advice which will provide the best protection available, and I make no apologies for that. And the proof you desire is quite easily obtained by the simple use of Google - I don't have the time or the inclination to do this for you.
The
best protection is not to use a wireless network at all but if someone wishes to use wireless then they have to work within the parameters of the device they have. With a device which cannot be upgraded to use WPA the only options are to use the security which it offers or to replace it - and the latter may not be an option for people with restricted budgets.
In our case the signal from our wireless hub can be picked up within a limited range due to its positioning in the building. That area (I've walked round outside to test it) is restricted to nine other buildings and the roadway. I've known the occupants of the buildings for several years and know that they are trustworthy. Some don't even own computers.
That leaves the roadway where someone might conceivably drive up and park for the purposes of finding a wireless network to hack into. Given the nature of the area the likelihood of that happening is very low. Consequently, the risk can be managed by use of WEP/MAC Access Control.
That's why I said last Saturday:
Like everything else it all depends on the risk of somebody trying to break in. If the risk where you live is high then of course you need the highest level of security - but if the risk is low then extra security doesn't have to be number one on the to do list.
Protection, whether doors & windows, wireless networks or whatever, needs to be adequate for the assessed risk - which isn't necessarily top of the range in all circumstances. That is not irresponsible or foolhardy, it is practical.
Graham