The short answer: No.
While each case may vary, most multiple account violations consist of players funneling resources, dragons, or items from one or more "side" accounts to one or more "main" accounts in an effort to quickly amass in-game wealth or advantage over other players. In other words, the use of multiple accounts is cheating.
Shared IP Addresses
It should be noted, however, that knowingly masking multiple account behavior behind this exception is not allowed. We know that many families or dorm rooms or clubs enjoy Flight Rising together on the same network, but each member of the network must autonomously maintain and play their own account. If a member loses interest, it is not permitted that their vacant account be used by anyone else.
Below is an example of a scenario that would be considered multiple account behavior:
A brother, sister, and mother sign up for Flight Rising to play. These family members exchange items, currency, and dragons while playing normally of their own accord. (No problem - this is okay.) Later, the mother and sister become disinterested in the site and give their remaining items and dragons away to the brother. (Also okay!) Afterwards, the mother and sister decide that they will log in every few days to only complete their gathering turns, pull from Pinkerton's Pile, and send the gathered items and Well Fed bonus currency directly to the brother. They no longer have interest, and no longer actually play for themselves.
This is where it breaks down and the violation occurs. The mother and sister have stopped playing, and the sole purpose of their accounts is now to benefit the brother's account. Whether or not the brother has login access to the accounts or not, all three are participating in multiple account behavior.
Gifting, trading, or sending items/dragons/currency between accounts (regardless of whether they share an IP address or not) are all acceptable forms of gameplay. It is when one player registers or uses "side" accounts that exist solely to benefit another that it creates a skewed and unfair gameplay advantage.
Cases like the above are always researched thoroughly before action is taken. When a closure occurs, players have the option to appeal the closure to have the case reviewed again.