Hamilton city councillors, eager to discourage militaristic white supremacists, are banning anyone who's not a licensed security guard from flexing muscle on city property.

But some worry that'll make it harder for volunteer groups who provide their own security at small rallies and festivals.

City council's general issues committee voted Wednesday to make a new rule that anyone acting as a security guard at functions on city property needs a provincial license.

This comes after the self-professed "patriot group" Canadian Three Percenters did security detail at city hall on July 29, when the Canadian Combat Coalition rallied against federal anti-Islamophobia Motion 103. Local anti-fascists counter protested.

Council is being "gravely naive" if it thinks these tense events won't happen again, said Matthew Green, the Ward 3 councillor who moved the motion. And one day, someone will get hurt.

"It's not a one-off event," he said.

With the new rule, Green said, when militaristic white supremacists show up for security detail, the city can charge them with trespassing.

Councillors voted in favour of this. But some worried it would unfairly penalize volunteer groups.

"I worry about the unintended consequences," said Terry Whitehead, Ward 8 councillor, while Judi Partridge of Ward 15 said she needed more information.

Green said later that he can't think of any group that fits that category.

Larger events hire their own licensed security guards or police, Green said.

Events on outdoor city property, or in the city hall forecourt, are booked through the city's special events advisory team (SEAT). Security typically isn't required when the event doesn't require opening a city building, says a staff report.

City council will cast a final vote on Oct. 25.