RE: `save-excursion' defeated by `set-buffer'

[Drew Adams]

> > FWIW, I also agree with Andreas that a "warning" is for 
> > something serious.  A warning is not the same thing as in
> > informative message.  A warning _warns_ you about potential
> > danger/damage.
> 
> Curious. In computing terminology, I'd say an *error* is for something
> serious. A warning informs you about a potential problem, and often
> one that you're likely to miss by yourself. Just like this one.

Problem, yes, and typically a serious one.  Not like the information in this
message, IMO.

An error message is typically for something that has already happened (or is
happening now).  A warning message typically warns you about something serious
that could happen (potential, future).

By way of example, in one computing company the documentation style guide says
this about a Warning notice:

 4.6.3 Warning Notices
 Use a Warning notice to call attention to a situation that is
 potentially hazardous to people. The warning notice should
 always precede the step where the risk occurs, and the text
 should always be in boldface font.

 Warning:

 To reduce risk of electrocution, unplug the machine before you
 begin repairs.

Note the emphasis on danger to a _person_, at least for this particular style
guide.  The same guide says this about a Caution notice:

 4.6.2 Caution Notices
 Use a Caution notice to indicate the possibility of damage
 to a program, system, or data. The caution notice should
 always precede the step where the risk occurs.

 Caution:

 Always use ________ to bring ________ online and offline.
 Using other tools can result in unintended _____ failover
 or jeopardize the integrity of your _______.

And it says this about informative Notes:

 4.6.1 Notes
 Use Note to call attention to points that might easily be
 overlooked. A note includes important hints, tips, guidance,
 or advice on using a program. It also includes information
 that is essential to the proper operation of a program or
 system, provided that the information does not belong in
 a Caution or Warning notice.

 Note:

 The installation stops and the system returns an error if
 the prerequisite software is not installed.

 Note to UNIX Users:

 This feature is not available for the UNIX operating system
 in the Beta software. Please install the current release
 before using this feature.

Those concern doc notices, not messages, but similar considerations apply.  Some
organizations do not distinguish Warning from Caution, but the main idea is that
these things warn you about a serious potential problem.  They do not simply
provide important guidance or essential information for proper use.  

HTH.