Communication standards?

Hi there, still pretty new to this site (as you can probably tell by my score). I just wanted to get some feedback on something.

One thing I keep seeing is that I'll send someone a message as part of a trade, and I'll check back later...they've logged in, but done nothing. No message, no confirmation, no alteration, nothing. They've just completely ignored it.
Then I'll check back even later...and again, they've logged in, seen my message, and done nothing. Completely ignored it. This will generally continue ad infinitum until I cancel the trade.
I would feel differently if they hadn't logged in and seen my message (hey, sometimes you need a few days away from the site, I get it) but - if I understand correctly - there's no possible way they could have missed both the message and the new trade offer.

Is this normal for Deckbox? Most of my previous trades were responsive even if it took them a little time, but lately, I'm seeing more and more people that will repeatedly log in and ignore my messages. Not even refuse the trade, just let it sit there forever, completely untouched. Since I'm the new guy here, I'm trying to get a feel for how common that sort of behavior is for this site.

Thanks in advance!