Let me tell you my experience. In general, there's nothing wrong with leaving your suitcase with the bell people. They guard it nicely and nobody is going to steal it or anything. They put a computer sticker on it, so they can't give it away by mistake. (And if they do, most people don't want your luggage; they will simply make the bell boy take it back.) So you need not worry about luggage loss at all.
What I do worry about myself is having them deliver it. For example, I had luggage brought over to All Stars Music once. They got the luggage before 4 p.m., (I knew because I called them and they said so), but they didn't deliver it to my room until 9:30. I tried it go get it myself around 7:30 p.m., but they said my luggage was with the delivery guy, so I had to wait. I sure waited a long time!
Another time, I had my luggage delivered at CBR, and they delivered it around 7:30 p.m. (even though they had it by 4). Another time, I had my luggage delivered at GF. By 5 p.m. I had no luggage, so I called them and asked is my luggage here? And they said YES! I said can you bring it? They said SURE! And they brought it within 5 minutes. My DS11 at the time said, why didn't they just bring it? What were they waiting for?
And for Pop, they do the same. The luggage gets delivered rather late, for my taste. They used to deliver it earlier, but it seems to get later as the years go by.
So the only concern about luggage for me is how late they might be to bring it. If you don't mind that, then it doesn't hurt a thing. Otherwise, you should just tell them to store your luggage and
not deliver it to your room, you will come get it. I noticed that at least this year, Pop has started letting people borrow luggage carts. I saw somebody with one 2 months ago and I asked them about it. So even if you have a ton of luggage, you can get one of those carts and push your stuff yourself with ease.
But in any case you don't need to be concerned about loss. I've seen people give the bell boys open shopping bags that don't even zip up (the stuff can easily fall out of there if the bag tips over), and I've never heard anybody complain about stuff getting stolen out of bags. The bell boys also handle grocery deliveries, which are all just paper grocery bags. They do a great job with it.
Luggage to the airport are checked in in the morning only. Otherwise, you can bring them with you and do it at the airport. Doing it at the hotel is generally easier. So the best way is to check luggage is in the morning before you head for Epcot.
