From the Policies page here on the website (says nothing about shoes, but provides a link to Customer Service for specific questions):
Costumes and WeaponsWeapons and items that appear to be weapons are not allowed at Gen Con. Self defense, recreational and utility items such as knifes, tasers, pepper spray, BB guns, cap guns, air-soft weapons, paintball guns, water guns, martial arts weaponry, including wooden practice weapons, etc., are not welcome, even if it is lawful to own and carry them in other public places. Off-duty security, law enforcement and military personnel are not allowed to bring their weapons to Gen Con. Items resembling futuristic weapons, fantasy weapons, and non-projectile boffer weapons may be allowed provided they are not handled in a careless, threatening, or destructive manner against persons or property.Questionable items can be brought to the Information Desk in the convention center during operating hours to be checked for compliance with this policy. Some events may provide exceptions to this policy under strict circumstances defined by that event. Items purchased in the Exhibit Hall which violate this policy must be wrapped and immediately removed from the convention premises.20th and 21st century uniforms may not be worn as costumes. These include any uniform that can be construed as a military uniform from any country or a uniform worn in an official capacity, such as security guard, police officer, deputy, fire marshal, paramedic, etc. Active duty military personnel are permitted to wear their government-issued uniforms.Gen Con Event Staff or security personnel may inspect any item or costume, or request that an attendee remove a mask, at any time during the convention. Failure to comply with these policies and/or the instructions of Gen Con Event Staff or security personnel may result in immediate removal from the convention without refund.If you have any questions about these policies, please contact [email protected] before the convention or visit the Information Desk in the convention center during operating hours.