Onions and tomatos

This is not as much a HUGE complaint like some people have, but when I ask for no onions, I mean no onions. Now I get that people are human, and I know mistakes are made. But everytime I eat at any McDonalds, they always put onions on the order, and sometimes (I checked and compared with my friend) MORE than my friend who got the same thing. And it still say no onions on the receipt. Now, I know this is kind of petty, but it was mainly the fact that they put it on the receipt, and did not do it that got me mainly. If the person taking the order did not put it down, of course the cooks would not know. But it was on the receipt, so the person taking my order must always put it down. And by the way, this is more than just one McDonalds, I live where there is one on every corner. Anyone else have this issue?