People who do business online, or even just set up websites as to which they want their users to agree to terms of use, which may also include specific business terms, are always anxious about the degree to which those terms will be enforced against users who violate them. Back in 2012 Zappos, Inc. (a subsidiary of Amazon.com) lost a case in Federal District Court in Nevada against users who, having been informed by Zappos of a security breach, sued as a class rather than going to arbitration as required by Zappos' terms. Now another similar case has arisen, this time at the Court of Appeals level, in the same Federal circuit that includes the Nevada court. The hapless online retailer this time was Barnes & Noble.
For some reason, an Israeli lawyer has just put forward a lengthy discussion of the Zappos case rather than the B&N one, but since the issues are pretty much the same it's worth taking a look:
http://shaked-law.com/electronic-signatures-enforcing-online-contracts/
Her analysis and recommendations are pretty straightforward, and are similar to what I would tell clients who need to rely on online agreements. Bottom line, when you need to know that a customer or user has agreed to something, make sure they have to take affirmative acts to signal their consent; and just to play it safe, don't put anything stupid in the agreement.