re: There is an easy way to avoid this threat:
Well free webmail is solving a problem your ISP isn't:
when you're not at home, how do you get your email?
Most ISP's I've used will allow you to log in to your email account from outside their network, but the connection isn't encrypted, so anyone sniffing on the network can abuse your email.
But you don't need access all that often, so spending the folding stuff on webmail access is a little redundant.
There's another reason for it, too. And one the ISP really doesn't want to help you with: if you use the ISP email, when you leave them you have to contact everyone to say you're not there any more.
Use webmail and you have one email address you don't have to change when you change ISP.
'course spending money on that is worth while.
And you are still locked in to requiring the webmail company to continue operating.