Jordan,
Marketo's system blocks most form spam, but not 100%.
See here
https://community.marketo.com/MarketoArticle?id=kA050000000L3EE
https://community.marketo.com/MarketoArticle?id=kA050000000KyqZ
https://community.marketo.com/MarketoArticle?id=kA050000000Kzd2
Handling personal emails is done via javascript - or you can use automation to route these leads once inside Marketo.
https://community.marketo.com/MarketoArticle?id=kA050000000Kyxo