I can honestly say that I don't remember encountering any particular limitations with using references to shared variables, nor can I intuit anything obvious why they shouldn't be just fine.
However, I also cannot remember any good reason for using references to shared variables.
And a quick search of my source files didn't turn up any obvious examples, but then it is a little hard to search for.
So both my instincts and experience are telling me that whilst I cannot see any particular reason for doing it, it should be just fine....
...but then comes this feeling that if you hadn't encountered some anomaly, you wouldn't be asking...
so, maybe I'll just keep quiet rather than get seen to be caught out by a sucker punch.
With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.