成隻成對？| The generalization of singular for plural counter with body parts in Cantonese

自從十年前我已經發現有哩個現象，大部分人明明指係一對眼、手、腳都會講咗一隻
It's bugged me for at least ten years that Cantonese speakers uses the singular counter 隻 when they are clearly referring to a pair (of eyes, hands, legs).  

網上有既例子：
Some attestations from the great Internet:

有咩方法可以令隻眼大d (How can I make my eye look bigger?)

我隻腳好大..好難買鞋.. (My foot is huge... I can't find shoes)

身高170嘅話隻腳無理由咁短 (Being 170cm tall, his/her leg shouldn't be so short)

照上文下理肯定係指成對眼／腳（唔通大細眼 長短腳咩）
It is clear from context that they are referring to BOTH eyes/legs (unless you only have one huge foot)
當然，用「對眼」「對腳」既人都有，不過口語裡面講「隻」已經被接受可以解做一對或者一隻。
Of course, there are speakers who use the plural counter 對 , but the usage of the singular in place of the plural has long been accepted. Its actual quantity is ambiguous 

例：我隻眼好痛 (lit. My eye painful)
－－究竟係一隻眼定兩隻都痛？兩個解釋都可以
-Does it mean one eye or both eyes? It's ambiguous. 

唔願意接受哩個約定俗成用法既人就會有以下既對話：
If you choose to believe that this usage is a corrupted form, you might have had this conversation before)
A： 你隻眼好靚呀... (Your eye is beautiful...)
B： 係？你講左眼定右眼先？(Really? My left one or the right one?)
A： ..... [The romance killer strikes again!]


但係隻＝對既用法似乎只係限於身體部分，而一對對既物件仍然係分得清清楚楚：
例：伙記，俾隻筷子我呀～ ≠ 一對筷子
Nonetheless, this singular=plural counter usage appears to be limited to body parts that come in pairs. As for objects that come in pairs, there is a distinction:
e.g.  If you tell the waiter "Give me a chopstick please," he will assume you drop only one and needs only ONE chopstick 


大家係咪都係咁用隻＝對？定係冇留意過？有冇試過因此而發生誤會？