Lo's stickers first appeared this year, and included an image of an older man stylised in black and white, with the word "Limpeh" - meaning "your father" - which is sometimes used as a rude phrase in Singapore.
Some have suggested that the man bears a resemblance to Lee Kuan Yew, Singapore's founding statesman.
Lo herself was unavailable for comment, but the petition has attracted a large number of comments criticising Singapore's repressive laws.
"Creativity requires a little chaos," wrote one poster.
Another, Gene Ho, argued: "I think it's tastefully done. Not political nor damaging to the nation ... Laugh at yourselves a little and maybe you will really understand what art is."
Singapore's police insisted that "the case is classified as vandalism", adding that offenders would be dealt with severely.
Defending the tough line, a police spokesman told a Singaporean website that it had diverted "substantial resources to identify the suspect involved" that had needed "intensive inquiries and legwork".
"This is on top of the considerable time, effort and cost to clean up the roads and affected areas. Vandalising public property is a very irresponsible act. Offenders will be dealt with in accordance with the law."
In the escalating row over her treatment - in a country where small businesses regularly put up advertising stickers but are rarely prosecuted - Lo has attracted the support of several members of Singapore's Parliament, among them Janice Koh, who has compared Lo's work to that of the British street artist Banksy.
She called on the authorities to handle the case "with a light touch".
Koh said: "It is almost impossible to talk about developing a culturally vibrant, creative or lovable city without some tolerance for those slightly messy activities that sometimes challenge the rules. For Singapore, it would be useful to make a distinction between this kind of art and outright graffiti or vandalism that seeks to deliberately destroy public property."
Not all those who have commented publicly, however, have been so tolerant, with several calling for Lo to be punished under the vandalism law.
One, Ann Hee Kyet, said: "This is definitely vandalism. Stop hiding behind the excuse of art."
- OBSERVER