I installed LastPass yesterday and was playing around with it. Later I wanted to update a DNS setting on my Netgear SOHO router. I lost the connection to the Internet.
The cause turned out to be that LastPass overwrote the Login and Password for the PPPOE connection to my ISP with the login and password for the router itself. If it'll help the LastPass developers, the HTML for the fields that were overwritten are <input name="pppoe_username" size="15" maxlength="64" value="-snipped-" type="text"> and <input name="pppoe_passwd" size="15" maxlength="64" value="-snipped-" type="password">.
Secondary username/password fields are also found on some web sites. For example, gmail allows people to configure a list of POP3 accounts and gmail polls them for messages. Will LastPass overwrite someone's POP3 logins with their gmail login data? Again, if it'll help, gmail's HTML is at https://mail.google.com/mail/#settings/accounts
and is <input name="ma_user" id="focus" size="30" onchange="onUsernameChanged();" value="-snipped-"> and <input name="ma_pwd" id="ma_pwd" size="30" autocomplete="off" value="-snipped-" type="password">.
While most web sites do not contain logins/passwords for other sites or devices a few do such as the examples shown above. What's the best way to prevent this overwrite of the login information contained on a web site?