Yes. However, in the highly unlikely event that SignRequest would "lose" some signatures it's really difficult to commit fraud with your signature alone.
If you didn't place your signature the signature has no legal value. More proof is needed than just the signature, like the context in which a document was signed, the ip and email addresses.
In addition, consider that your signature can be copied from any document you have signed in the past and the signatures of many CEO's, celebrities and politicians can be freely found on the internet.
For more information visit our security page.