I was too paranoid to put the bed against the wall, for the same reasons as your acquaintance. For a while, I had a co-sleeper on one side to 'catch' DS if he ever rolled off the bed (he didn't actually sleep in the co-sleeper lol, and he never rolled off). Then we just put our mattress on the ground & I far preferred that. DS didn't roll off occasionally until he was older (6mos to a year, around when they start crawling/walking) and he was fine when he did roll off, it was only about 6 inches and we have a carpeted floor. He didn't even wake up when he rolled off most of the time lol -- plus it was easier for him to climb on & off the mattress with it on the floor, and safer for jumping on when he got old enough for that!
He nursed a lot at night so depending which side he was nursing on, sometimes I had him in between me & DH, but with a firm pillow between DH & DS. That worked fine too but I know some people would be uncomfortable with the pillow being in the bed at all. It was fine for us because of the way DH slept and DS always stayed close to me and the pillow never moved.
Just for the record. my DS is 2.5 now and we now have a regular-height bed (mattress and box spring) and DS sleeps between us with no barrier between him & DH anymore.... so you don't have to worry about these things forever!! But I still won't put the bed against the wall, I'm terrified of entrapment!!
(sorry, I'm a bit long-winded sometimes...)