I thought about and considered all comments so far, the model for giving away accounts, if there is something scripted the best possible outcome for the scripter would be: they can then make tons of accounts, true. Then set up a service selling access so the storage capacity of those accounts, for a lower price.
So if a person can generate the equivalent of some arbitrary amount of space: 50,000 safecoin worth, and sell it off for 5,000 actual safecoins through an app service. And it could be to publish public data for cheaper. It would eventually run out, and the network would have by the end of the running out filled up with plenty of content.
Indeed just downloading and running is a direct approach, and farming probably will involve more commitment than just turning on and off your laptop every few hours.
A thought on giving people access and not jumping around could why not make a promo code unique one each one, and limit its distribution. And distribute that code and the client application that accepts the code. Which opens up the possibility to have some storage allocation, and this way the code was got physically, or communicated somehow and that could be the solution to dos by some scripter.