The funny thing is that the longer magazines used in the M1 Carbine family seemed to be called "banana clips" by the troops as often as not. Imprecise or erroneous language, used often enough by enough people, eventually can make an incorrect term correct by way of common usage. Witness the term "assault rifle" we all know that the term can only be correctly used when refering to a select fire rifle of medium power (generally 5.56mm NATO or 7.62mm Soviet and variants thereof). However, through common misusage, the term "assault rifle" is more often recognized as describing semi-auto only versions of military rifles And cosmetically similar firearms. The technical difference still stands, but in the minds of 90% of the populace when you use the term "assault rifle" they instantly assume a semi-auto military style rifle and the distinction between select fire and semi-auto only is lost on them.
If someone says banana clip to me, I just about instantly think about the large cap M1 carbine mags, because I have heard them mis-termed so for as long or longer than I have heard them called anything else.