i know there are a lot of mixers where you can switch off the crossfader altogether, i think the xone mixers have switches for this, as well as a lot of numark mixers.. my vestax mixer (pcv275) doesn't but i should imagine a vestax with more than 3 channels would. you will generally find that if the mixer has a crossfader that is assignable then you can also switch it off..

i do however think its a good idea to get into the habit of checking the mixer before you start mixing to make sure everything is how you like it. not noticing the crossfader being on one side before you do the mix is a schoolboy error

___________________
MUGGETS

Not so much not noticing its to one side- its more smacking it by accident or catching with headphone lead and pulling it across thats a pain.


Most 19" mixers with 3 or more channels (especially modular ones) have to have the ability to choose which channel to assign to the x fader, so by that process its also turn-off-able (thank god).
Cloud, vestax pcv505 (i think) and most formula sound (yuk) ones do

My favourite mixer (the cloud) has kill functions which are enabled by assigning the channel to one side of the x fader- but thats not a problem, as the fader has a notch in the middle- and its also to the side of the mixer- not plonked in the middle in the way.