Can I limit the number of entries that a person can submit?
Settings > Registration > Registration limit for general settings and Settings > Categories for per category limit
In Settings > Registration > Registration limit you can choose to allow one entry per registration, or multiple entries. If you choose multiple entries per registration, you have the option to set a maximum number of entries.
In addition, when creating your program categories in Settings > Categories, you can set the maximum number of entries that can be registered for each category.