I think the designer comes off as a complete tool in this one, unintentionally. You'd think that the bag would have gone through some stress test if it's going to sell for that much. I mean, if Alvin didn't break the thing, it would have fallen apart anyway. Though it's weird because everyone kinda came off a level of jerkish. Brit was being nasty and shoving the win in Elenor's face. Elenore wasn't exactly a gracious loser. As much as Alvin was trolling Brit, I'd say Brit and Elenore had just as much coming to them.Alvin is a jerk some of the times, so it is justified in certain cases. Though I could definitely see him blaming the bag's design rather than himself for breaking it.
As far as Alvin's disproportionate retribution goes, the episode that kinda bugs me is the one with the robo-parent device. I know Alvin's an egotistical wad sometimes, but that episode really felt like Alvin was getting his butt handed to him by the writers.
Then again, if there's one older episode that I've always had a problem with, it's the one where Alvin puts Theo in a wrestling match so they can win money to buy some appliance Theo wanted. And even then it's for cooking food for others, but that's not important. I know Dave likes to teach the kids humility, but I really disliked the outcome of the episode. In other words, Theo risks his life for money in a wrestling match only to lose it all because some weirdos that decided to dress nicely for wrestling got their clothes soiled at a wrestling match and Dave tells them the money that Theo earned by putting his life in danger should go to the dry cleaning of idiots that knew it was a wrestling match and dressed to the nines for it.