User Volker Wulf (in message "wikisyntax in text attribute") tried to disable parsing in string using <nowiki> tag and reported "funny characters when I ask".
I reproduced for Type:String. I found the annotation
[[String test::<nowiki>Don't parse this [[Test relation::Sandbox2]], what happens?]]
- Displays the exact text in the page (good!).
- Displays "UNIQ4771b2c964a25267-nowiki-0000001C-QINU" in inline queries.
- Displays garbled wiki markup instead of the magnifying glass in the factbox (bad).
It was hard to get MediaWiki to parse wiki markup in strings for SMW 1.0, now it's hard to turn it off!
There's undoubtedly some tricky way to use markup or HTML to disable parsing but it won't be easy for naive users or automatically-generated semantic annotation to apply it.
SMW could provide a different datatype for unparsed text, e.g. Type:Unparsed_string, or a special Property:DontParse that you put on certain properties. Neither is attractive.