By Vince Gerasole

(CBS) — Pokemon Go is one of the hottest games around, but many public ‘Pokestops’ are in public parks, which often close overnight.

If players aren’t careful, it could cost them money.

Dozens of players are drawn, for example, to Bode Lake’s Pokestop–a place to hunt down the game’s virtual creatures–near Streamwood.

However, when 31 players ignored an officer’s warnings to leave at the park’s sunset closing last Friday, they were fined $75 each, CBS 2’s Vince Gerasole reports.

Some players admit its easy to lose track of time, running around catching the critters.

Saul Hopfensperger admits he has “played until four in the morning before.”

“I try not go out too late at night,” said one young woman playing along Chicago’s lakefront.

And it’s those late night adventures in public parks that can get people in trouble, as they typically close by 11 p.m., or even at sunset.

Vaughn Bullock, who helps run a website called Chicago Pokemon Go, understands the fines, but he also hopes officers will let first-time offenders off with just a warning.

Bullock’s meetups at places like Millennium Park downtown have drawn thousands of people.

“It has grown exponentially,” he said. “This game is bringing people outside more and having fun.”

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