There is talk of a repeat of the massive incursion into Egypt from Gaza a few weeks ago, only this time headed into Israel. The assumption from the left wing protesters is that the reaction would be similar, namely that Israel would do nothing, just as Egypt did nothing.
The reality is that would hardly be the case. Egypt did not consider those in Gaza an enemy, there was substantial support for relieving the suffering of Gazans within Egypt, and because of the relative isolation of the Sinai Peninsula, there was little real concern within Egypt. The primary purpose of the Egypt-Gaza border is to force Israel to assert authority over Gaza. Only secondarily is it to reduce militant influences from Gaza upon those in Egypt.
Thus, it makes most sense as a simple policy matter for Israel to continue to weaken the Egypt-Gaza border and to threaten to destroy it altogether should Gaza continue to pose problems. Egypt will have the choice either to enforce Israel's embargo on its side or face the certainty that Gaza will once again come under its sphere and not Israel's. The falsehood that Israel alone is isolating Gaza cannot be maintained long-term. It was abundantly clear that relief can come more readily from the West than the East for Gaza.
Thus, should there be an attempt to enter Israel en masse from Gaza, Israel should BOTH prevent that AND create opportunities for Gazans to enter Egypt. Obviously, Gazans would pose an immediate threat to Israelis should they enter Israel, even peacefully. Would NO MILITANTS enter? Would no bombs be brought across the border? Of course they would. Thus, no "non-violent" march could be allowed.
I would suggest that Israel use its array of non-lethal means of deterrence, but that it use any means necessary to prevent large scale bloodshed that would certainly result from masses of Gazans interacting with masses of armed Israelis rushing to prevent an invasion. I would further respond to a mass march from Gaza with an invasion from Israel and the destruction of the Egypt-Gaza border. Relieve pressure on that side. Free Gaza to the West.