I heard of a situation where someone took 10 mL of Diethyl Ether - put a few mL of water in it and allowed it to evaporate in a fume hood.
Some sharp criticism was given by others as to doing this - as the flammability issues, etc. with ether.
While care needs to be taken, I think there is a stigma that even the smallest amount of ether being used in a fume hood can spontaneously combust - and I'm not talking about 5 year old ether or at 100 F or with a hot plate or anything.
To be on the safe side - it is always good to be cautious, however, to gain some more understanding of the issue the following article was found - makes one feel better about fume hoods.
http://www2.umdnj.edu/eohssweb/aiha/technical/25percentLEL.pdf
