The answer in short is No. If TZ is embedded into the event, the Indexer will trust the embedded TZ explicitly and ignore any instructions that are given regarding timestamp in props.conf, irrespective of variance.
The longer answer is that Splunk may not automatically recognize the TZ offset expression. If you're using a common pattern, Splunk should recognize it, but if it's less common you may need a TIME_FORMAT to specify where the offset is located.
I just care about the added workload of having to process a TZ at all vs having the event use GMT (or the same TZ as my indexer.) Sounds like there is no added "load" with an embedded TZ.
This is incorrect; you can use
TZ_ALIAS to override in-event
TZ values (see my answer).
Actually, @jbsplunk is correct. The timestamp on this question was from Feb 26, 2013. At the time, Splunk 4.3 was the de-facto version, Splunk 5 would be released during .conf2013. So according to the correct documentation, http://docs.splunk.com/Documentation/Splunk/4.3.6/admin/Propsconf, the
TZ option was the only option.
TZ_ALIAS wasn't an option until Splunk 6.0.