I think it depends on the mother and on the father, but also on someone's definition of "spoil". My definition of a "spoiled" kid is a "brat" who doesn't respect his parents, anyone else, or anything else; and who doesn't appreciate what he has and isn't generally a nice person. Some "spoiled" kids are kids who are given little; and as a result, they're less willing to share the few things that they get.
With my kids (two boys and a girl) I was the one who made sure they had all kinds of things (both to supplement their learning and to make them feel special, and feel as if they were kids who were "have's" rather than "have-not's". I was also the one who talked them about how people who give them things work had for their money, and about how when someone gives a child something it's because the person wants to make that child happy and help him have something special. I believed that if my children saw my generosity they'd see an example of sharing and trying to make other feel special, not just by being given special things, but by having special times together with me and/or with their siblings, father, and me. My kids' father saw what nice, well behaved, kids they were; so he agreed with my approach. He wasn't awfully "hands on" when they were little, though. Today, they're grown and he is incredibly generous with them. The difference is that now they're also "generous back" to both of us. The value-teaching was my doing, though - but I was also responsible for most of the giving-stuff-to-them too (well, I, and their grandparents and aunts).
There would be times when I'd let them know we couldn't, say, get anything extra at the store. At other times, I'd tell them it was a day when we'd be buying something extra.