I remember once I had to deposit money in Santander but Thier machine had ran out of envelopes, luckily enough I was also a nationwide customer and the branch was directly across the street, so across I pop and got a deposit envelope which I then used in the Santander machine… 
(It may have been abbey national at the time) I was a regular customer at the time and the next time I was in they told me that they found it very funny…