Pros and Cons of unsecured wireless network?

"Pros:

You don't forget the password
You don't have to tell guests the password
You can feel good about sharing the internet

Cons:

You have to be more cautious about what is being sent over your connection in case someone is sniffing your packets
Bad people might come on to your network, do illegal things, and have you blamed for them (not likely, but possible)
Security in general. You never know what computer will hook into your network, inadvertently infect all the computers on your network, then leave.

I like to have two wireless networks: One public, for visitors and people nearby to use, and one private for my computers so that I don't have to worry (as much) about foreign computers spreading their viruses."

"In addition to Dan's answer, if you're running an unsecure network, you should make sure that the access to the network configuration is at least secure. i.e. don't use the default password on the router!

Obviously if someone did log into the router and change things, having physical access means you will always be able to hard-reset and claim it back, but it's something to be aware of."