OY! I thought that this was the stuff of urban legend.
I understand that people are afraid of spiders. (Myself, am allergic to them - have gone into ana ana ph - you know, the thing where you get all swelled up and can't breathe) after having been bitten. Around here, we have brown recluses who do amazing damage (have seen this firsthand), so of course I wear gloves when I garden.
Killer spiders in bananas, though? Old one. Probably about as likely as the scorpions in the Peter Mayle story, too (sigh).