No, there must be another and a much graver explanation.
A chain of circumstances flashed through Ulyth's mind, each unfortunate link fitting only too well.

The evidence seemed almost overwhelming.
Rona had been present at the meeting by the stream when Tootie incited the juniors to some secret act of rebellion against the school rules.
What this act was the occurrence in the garden had plainly shown.

That Rona had been implicated seemed a matter of certainty.

Her brooch had been in the possession of the cake-vendor, and she had chocolates in her bedroom, the acquisition of which she had refused to explain.

Did she intend to keep the pendant and exchange it for confectionery?
Her pocket-money, as Ulyth knew, was exhausted, and she had hardly any of the trinkets that most girls wear.
"Ulyth Stanton, you are not attending to your work.