Yes. They are standing OVER it, but unless one or more of their feet is actively on it it can still be opened with them there.
The way I tend to play these games, this sort of thing is determined by the dice. You roll bad enough when trying to open it, the dice are telling you something is wrong. It could be rusty, twisted, jammed, or in a case like this, very likely stood on.
If you move them first, that last excuse goes away. Does it lower the DC of opening it? Maybe, but it won't matter that it does if your roll is either high enough, or too low. And perhaps someone will think of something clever to either adjust the DC further or allow a reroll, or make their own attempt.
Does that make sense?