My first thought when I read this was what off flavours would be imparted to the wine though an improperly cleaned blender.
Say the blender was used earlier in the day to make hummus dip or a salmon mousse?
Getting rid of the oils from prior use requires a lot of soaking in hot soapy water and liberal applications of baking soda. & wine picks up flavours quite easily.
That's why I'm going to use my hand blender (Cuisinart Smart Stick from Costco). Since I haven't found any real use for it there won't be any flavors to be picked up by the wine. Besides, it's quieter and classier looking than the Margarita machine.