exactly this,
however, my old boss used to be a proper cunt with shit like this, the best example would be, "Right! were behind schedule, Saturday were working" so I cancel my plans, friday night after training with him (instructor / boss same person) "You know what, lets not bother tomorrow" happened multiple times, another one " working this saturday and sunday" go to work, he stays with me from 9 am, to 11am, he leaves and on his way out "pack your things for 12 and go home" then have the gall to say were behind schedule, I didn't mind doing a half day, but on a sunday its a piss take in the painting industry but again I wouldn't mind but the fact my folks used to have to pick me up (wasnt driving at the time) and hes going past my house less than a hour before I finish, it was a joke,
but money is money and we do what we must to get where we want, consider yourself lucky you can do it from the comfort of your place, but if you really don't want to do it, and you have a andriod / smart phone, just reply to the email and say youve already left the house and are with friends, thats the one I used to use can't do shit then or peanlize you for it