What Starlight did was theft, regardless of her reasons. You can’t trade away something if it’s not yours to trade.

@Frustration in Excelsis
 
That’s what I liked about this: neither side was 100% correct, so the conflict was gray.

@AC97  
For that matter, Trixie did make an active attempt at hiding that any offer of exchanging the wagons had previously been made – she didn’t say “this guy offered to trade caravans but I said no because of such-and-such reasons”, she acted as if no offer had been made. If she hadn’t done that, Starlight would have known ahead of time that Trixie actively resisted trading her wagon and had reasons for not wanting to give it away, rather than thinking as she probably did that the trade was an on-the-spot thing with no previous baggage attached.
 
Now, this still doesn’t excuse her impulsively giving away someone else’s property, but if they had been more communicative earlier in the episode this probably wouldn’t have happened.

@Background Pony #3547
 
Not to mention that as far as Starlight knew at the time, the wagon didn’t have sentimental value to Trixie. In her mind, she was making an entirely rational decision, and doing her a favor. Trixie complained about how cramped it was too, and she never mentioned sentimental value up to that point.

@HumanGhosts  
It really wasn’t like that. she didn’t just spitefully traded Trixie’s wagon, she actually did it with good intentions, she tried to improve their situation by getting a better caravan. yes, she’s still obviously in the wrong because she didn’t ask trixie’s permission and impulsively just traded away. but I still think context is quite important here, because the writer of this episode utilized these characters flaws quite well. this scene is a prime example of that.

That wagon is really important to her Starlight, Trixie treat that wagon as a home which is her only home and family. You don’t just sell something that isn’t yours.

Yeah, that’s the big problem with this episode. It was supposed to show a spat between two friends, but Starlight is so obviously in the wrong. It’s like if my friend drinks the last can of coke, so I shoot his dog.