We had planned on using 2 rewards on the same day. The shark reef aquarium at Mandalay and the 2 dinner buffets at MGM. We arrived at Mandalay to a fairly long line. I needed to join MLife because i've never had a card before. After around 20 minutes of waiting it became apparent that this was not going to be a quick process. At somewhere around the 40 minute mark one of the employees came over and had all of the people redeeming MyVegas rewards move to another line and allowed everyone else to wait in the original line. This left only a few people in the original line. They seemed to be having trouble redeeming the rewards, I don't know if the people were new behind the counter or if they don't see many of these awards, but they didn't look comfortable. I'm 2 away from the counter and people in the line start to notice that new people are walking into the now emptied line with MyVegas rewards and are getting service right away. I'm not a complainer but the 2 ladies in front of me where being vocal at their annoyance. After finally an hour of waiting I make my way to the counter. We had arrived at Mandalay late in the day and I came to the conclusion that we no longer have time to visit the aquarium. We had planned on spending roughly an hour there and that time was wasted standing in the MLife line. It was finally my turn and I was called over to the section of the desk that had been designated to handle the recently shortened line. So yes, after being moved into the new line and watching the old line empty and new walkups helped, I was finally back where I started. The most frustrating thing was the rewards can only be redeemed at the location that you will be using the rewards. This was something I hadn't seen mentioned anywhere else. I could not have my MGM buffets loaded on to my card by employees at Mandalay Bay. The employee helping me wasn't aware of this either. So after an hour of wasted Vegas time I was informed that I would need to go and wait in another line. I was able to get my MLife card but that was all that was achieved for an hour of my time. Thankfully the process was quick and painless at MGM. I'm sure my story is probably not the normal experience for redeeming rewards. I mostly wanted to point out that you need to redeem your rewards at the property they will be used at. If you plan on using a couple of different rewards that are at different properties be prepared to wait twice.