In and of itself it's fairly innocent, but put it alongside Watchtowers constant demands to donate donate donate your time and your money, it is easy to see it fits in with their message for JW's to be generous and donate to the WWW.
This cartoon strikes me as a 'primer'. Generate that generous spirit first - then later the Watchtower will direct that generous spirit to the contribution boxes. The article of the chicken Julia mentioned are a great example of that.
I don't think I'm being paranoid by saying this, it's cumulative evidence of their manipulative techniques that make it obvious.