"My commute which is currently an hour is now going to involve three border crossings each way - that's six border crossings every day", environmental scientist and border resident Patricia McGenity, said at the protest, organised by "Border communities against Brexit".
"So far we know what the British parliament says no to, but we don't know what it might say yes to", he said.
His comments come as Ireland is set to face increasing pressure this week over the issue of the Border in the case of a no-deal Brexit.
The Great British pound came under renewed pressure at the end of last month, starting out April on the back foot following PM May's withdrawal agreement being voted against again and as markets struggle to project a way forward for Brexit at this juncture as the United Kingdom heads towards a disorderly Brexit on 12th April.
He claimed the establishment of a cross-party government would be in the "national interest" and help resolve the Brexit crisis.
The Irish taoiseach Leo Varadkar has been adamant that the European Union will not budge on the issue.
Ms McDonald said: "We are at a very risky moment where we inch ever closer to the real possibility of a crash and a chaotic Brexit".
Mr Weber said that Ms Merkel, Mr Macron and other European leaders "are close to our Irish friends" and he said the 27 member states have been united on the Border issue.
Sergio Aguero's fitness could be the key to Man City's quadruple bid
Parker said: "While it's still mathematically possible we won't give up, but I'm a realist and we all understand the predicament ahead".
Bertie Ahern, who led Ireland from 1997 until 2008, said that Mrs May "should be arguing that the single market was made by British politicians and not saying that it's great that Britain will be out of it". We have reached this view from a principled position as we do not believe the withdrawal agreement is the best way forward for the United Kingdom.
Mr Weber said there was no interest in a hard Border: "That is not our idea".
"Westminster has rejected for a third time the Withdrawal Agreement which includes minimum safeguards for Ireland, North and South".
"The United Kingdom needs to urgently present an alternative plan in the next few days".
The party's Brexit spokesman Sammy Wilson said its position was fixed.
Lawmakers vote at 1430 GMT on May's 585-page Withdrawal Agreement at a special sitting, but not on the 26-page Political Declaration on future relations, a manoeuvre to get around a ban on repeatedly putting the same submission to a vote.
Meanwhile, a Sinn Féin MP has accused the Democratic Unionists, who prop up the Conservative Government, as being detached from the reality of Brexit.