it could be illegal for non nationals to be within certain syrian locations.
there are 3 sides fighting in syria, all 3 wont be to kind to unknowns, as they could be supporting any of the others.
Regardless of nationality, people who are labeled as humanitarian aid have invariable immunity to national laws. If they commit a crime then it has to be taken up with whoever authorized their status, and the trial can't actually take place on their soil.
If a group of civilians were to walk into Syria without any form of identification or authorization then the Syrian government has the right to apprehend them (not kill them). However, if there's an agreement made with like, say the UN or another global organization, then they can get diplomat status and be virtually immune to any sort of threat.
Russia hasn't proven very willing to work according to international norms and laws.
As for peace in Aleppo, "You make a desert and call it peace." is sadly likely to apply.
I'm with you that it'd be nice if this march were to work out, but the reality is that it more than likely will fail. Either these people, be they normals or land whales, will tire out or run out of money and return to their day jobs or be turned back by force or turn into an unruly mob. It would be nice if it were otherwise, but that's more than likely how it'll play out. Cross our fingers though.
Well you can't just say to the schoolyard bully "i'm powerless against you so i'm going to let you continue bullying me" because then you're just allowing it to continue and securing your role as a coward.
I agree with the fact that they might fail, but if they get enough support they could actually get help from the german government or possibly the United Nations to help support their walk. Think of it like a legal protest and how there's always police around to defend the protest and make sure nothing happens to the protesters.