I see that as learning from the Mendenhall situation. We had zero data on Mendenhall, yet he was ranked the top RB on the board when we picked. He was certainly not one of the guys expected to fall to us. When he did, we essentially jumped on him. Or, at least that is how I recall it happening. Not saying that is 100% fact. But, bringing in guys like Parker and Perriman at least allow us to have data on them in case they do fall to us... or are most likely the guys there. Would we take them? Hard to say, considering we don't know how they interviewed. Looking at the list of guys we've had in, it just reads like guys who are likely to be taken around our selection... and doesn't truly indicate that we intend to trade up.
Not sure exactly what you meant by "trade up" --- maybe a typo --- but I agree they are just trying to be prepared for any scenario. You have to do that when you're drafting at #22, it's not like picking #4 when you've got 4 guys you would happily snag.