[aidenn0]

IANAL, but while you cannot totally give up your right to sue, you can voluntarily restrict it.

For example, you can agree to resolve disputes in binding arbitration, and then you could only sue on the grounds that the arbitration was in some way unfair.

Similarly you can agree to not take part in a class-action suit, while still being allowed to sue as an individual.

Now that only applies to contracts that are negotiated. Contracts of adhesion (a non-negotiable contract when there is a disparity of power, like an EULA between you and Microsoft) have a lot more restrictions.

It looks like Pay Pal is trying to get around this by allowing users to opt-out, thus making it negotiable. I'm not sure if there is precedent for that. Those who are actually lawyers might know.