It is strongly recommended for vendors to get in contact with PayPal at least 2 weeks prior to a launch to discuss your upcoming launch, projected earnings, provide proof that you can support the 'sudden' increase in business, and further clarify any questions PayPal may have.
Having this conversation prior to a launch can assist in disabling certain risk flags that cause a seller’s account to be restricted due to high volume.
Please also keep in mind that you can't have a $0 balance. We have had many cases where Sellers can't make sales when they have a $0 balance and all attempts at purchases were auto reversed. This was resolved by adding a balance to their Paypal account. Therefore you will need to keep a balance in your Paypal account before launching your products to ensure that you will not have this issue.