The Ibrox club is facing a hefty bill from their Scottish Cup opponents after the incident at the end of the fourth-round match.
A large hole was burned in the playing surface - which the Bairns had installed at a cost of £450,000 in September - by the flare. The SPFL Championship club has drafted in an expert from the Netherlands in a bid to get their under-20 game played tomorrow night.
The SFA could also take action and impose a fine. Rangers Supporters Association general secretary Drew Roberton was at the match televised live by Sky Sports. Robertson fears it is only a matter of time before a supporter is seriously injured by a flare or smoke bomb at a match.
And he hopes Rangers send out a clear message that such conduct will not be tolerated by banning whoever was responsible.
He said: "I was right in the main stand in a seat that was right on the line with the corner flag. I wasn't far away from it.
"It was shocking. These people have to realise this sort of behaviour is totally unacceptable.
"Rangers will obviously have to compensate Falkirk now for the damage done to their playing surface.
"But it is not just hurting Rangers financially. These idiots are also damaging the reputation of the club and of the fans.
"These people are not welcome at Rangers matches. I don't think it will be long before somebody gets seriously hurt by a flare or a smoke bomb being set off. It has to stop."
Roberton added: "I don't know if the club can identify the fan or fans responsible.
"But I'd like to think they would do everything they can to weed him or them out.
"I would like to see whoever was responsible brought to account so that a clear message is sent out that this is unacceptable.
"Somebody knows the people responsible. These are the same people who would be up in arms if any other group of supporters came to Ibrox and damaged seats or whatever."
Rangers apologised to Falkirk after the match on Saturday and have promised to pay for any damage.