not exactly sure what youre basing your statements off of. the organization isnt any more or less radical as a result of its being banned...IT WAS ALREADY BANNED for years. the muslim brotherhood ruling the government, ironically, is much more trouble than your hypothetical situation listed above.
Passport control employees at Ben Gurion airport to strike between 11 A.M. and 1 P.M. (Haaretz)
from the article: Stand-off in Cairo mosque as Egypt considers Muslim Brotherhood ban