Some days we have flexible schedules and some days we don't because I have big plans already made. It was rude of the dad to assume that what I had planned for the day was less important than what he had planned for me for the day - um my daycare, my plans. Does it take much to have a child make a card no - but it would be a piece of paper folded in half with me printing Happy Birthday Mom on it and child scribbling with crayons on it taking only a few minutes while I made lunch and not detracting from our day. The other kids would get to do one too.
Actually I would probably just do it for all of them and write To Someone Special on the front and then let them draw on the inside as they wanted. I would not turn it into a craft that used my supplies, etc. as that is not what I am paid to do.