01-16-2013, 11:06 PM
I don't think you can use the guest account since that is wiped clean every time. I let kids play in there since they can't do much damage 
I would try to make the computer log in automatically but kick in the screensaver avter about 1 minute and in security preferences you can set the screensaver to ask for password. If there is indeed a power failure, it is very unlikely that the house sitter is there the minute the power comes back, and if they are, they probably check other things, not the iMac. Also If the house sitter is really mean they could unplug it, plug it back in and wait till it starts and then use your account before screensaver kicks in, but chances are they will not do that (otherwise you should not trust them with your house).
I would try to make the computer log in automatically but kick in the screensaver avter about 1 minute and in security preferences you can set the screensaver to ask for password. If there is indeed a power failure, it is very unlikely that the house sitter is there the minute the power comes back, and if they are, they probably check other things, not the iMac. Also If the house sitter is really mean they could unplug it, plug it back in and wait till it starts and then use your account before screensaver kicks in, but chances are they will not do that (otherwise you should not trust them with your house).