As the government defends the more than $1 billion security price tag attached to the upcoming G8 and G20 summits security experts suggest authorities should be preparing to deal with a familiar group of anti-globalization activists known for instigating violence.

The protesters, usually clad in black and who hide their identities with hoods and masks, are self-described anti-corporate anarchists known for hurling rocks at police and smashing store fronts. The group isn't organized. The term Black Bloc refers to a protesting technique.

Security experts claim these types of protesters represent the one to two per cent who incite violence and vandalism at international summits and they’re the main reason security costs are so high, published reports suggest.

Meanwhile, businesses in the Entertainment District are concerned about lost revenue in the days leading up to and during the G20 summit.

Local bars and restaurants are doing their best to let people know they’re still open for business despite the security clampdown.

Some establishments are even offering special Summit Deal discounts during the international meeting June 26-27.