I’m not sure but most people around me speak negatively about Dropbox in terms of security. The most common expression is: “Things on Dropbox are to be considered public.” My assumption is that anyone can achieve reasonable security of they care enough about it, therefore I would blame Dropbox management for their priorities there. Given the business of HelloSign, that feels like a possibly dangerous combination.

However, I agree with you: “offers to buy” would be more neutral and feel more appropriate. “Snares” has other nuances (surprise, violence, asymmetry) but neither convey a discussed at length, mutually agreed and beneficial relationship.