Rock 'n roller cola wars

Coca-Cola threatens Sodastream for using empty Coke bottles as part of displays of waste generated by bottled soda.  Ignore the misuse of "incredulous"; interesting that the objection was made in South Africa, which among other things actually has some case law protecting communicative uses of trademarks.  I don't know if that extends to truthful commercial speech, though.  It seems pretty clear that a trademark claim would fail, badly, in the US, though we can probably think of a bunch of names for the doctrines explaining why.