What do these mean?

[Anonymous]

Hi,
Please tell me what do these mean.

1. He has a high/low profile.
2. Everything is accounted for.
3. Fool me once, shame on you; fool me twice, shame on me.
4. [A new headline] Doctors tell former President Bill Clinton that he needs heart bypass surgery. [What does 'bypass surgery' mean here? Is it a kind of implant surgery?]
5. New security cameras keep watch over the store/bank. [What does 'keep watch' mean'? Is it just 'watch'?]
6. There's no difference as far as I'm concerned. [What does 'I'm concerned' mean' here? Is it the same as 'I know'?]
7. There're no mistakes as far as I'm concerned. [Is this the same as "I can't find any mistakes.]

Thanks a million.
Ann

[Rusty]

1. He has a high/low profile. (This means that he appears a lot or very little in the news media. He is often/seldom seen in public).
2. Everything is accounted for. (All the questions about it have been answered. If you have a list of things, everything has been checked off).
3. Fool me once, shame on you; fool me twice, shame on me. (If I fall for your deception twice it is my own fault).
4. [A new headline] Doctors tell former President Bill Clinton that he needs heart bypass surgery. [What does 'bypass surgery' mean here? Is it a kind of implant surgery?] (Yes, they take blood veins from the legs to replace some veins leading to/from the heart).
5. New security cameras keep watch over the store/bank. [What does 'keep watch' mean'? Is it just 'watch'?] (Yes).
6. There's no difference as far as I'm concerned. [What does 'I'm concerned' mean' here? Is it the same as 'I know'?](More than that, it means that it (something) neither affects me positively nor negatively).
7. There're no mistakes as far as I'm concerned. [Is this the same as "I can't find any mistakes.] (Yes).