The current geopolitical outcome of Egypt accepting large numbers of Palestinian is that Israel does what it is doing now to Palestine, to Egypt at some point in the future.
Jordan took a large number in the past and they were terrible guests -attempting to overthrow the sovereign government- and got expelled. Black September left a very bad taste in nearly everyone’s mouth. Governments friendly towards Palestine are very much against physically taking them after those events
Also, why would Egypt let in those that might provoke conflict and war with Israel?
It's a fools mission, and one which Egypt was quite clear on in November/December it didn't want to embark on.
That border is even more tightly controlled than the Israeli one AFAIK.
Also, some useful conext:
The Israeli border wasn't always like today. It has been progressively tightened step by step as nutjobs on the Arab side used whatever leeway they had to stage suicide attacks and smuggle in rocket parts.
From Google: ================= Egypt, however, has warned against an influx of refugees. It facilitates humanitarian aid into Gaza, but has said a mass exodus of Palestinians out of Gaza into Egypt is a red line, saying it fears Israel might never let the Palestinians go back. =====================
And Egypts real fear is that the Palestinians in Egypt will try to take back Palestine. Which wouldn't be very good for Egypt and engage them in a war with Israel.