A good magician with enough practice won't get caught at any angle when performing, and if that were so, the spectators along with you must realize you are their for entertainment mainly not to shock their world and start a new religion of Spongballites....I'm sure if you have them watching from other tables then your magic has entertainment value anyways.
Are you talking about the multiplying spongeballs effect specifically, or magic as a whole when you say this? I don't own the multiplying spongeballs, so I'm not aware of their angle limitations, but if you're suggesting this is a general rule for all magical effects, I have to disagree. Some tricks have angle problems, and there's nothing you can do about them. I don't care how much practice and/or skill a magician has, the balducci levitation can't be performed completely surrounded.
As for being entertaining, yes that is important, but so is being deceptive. If I go to a concert and the musician is great with the crowd but can't carry a tune, I'm going to be disappointed. Same with magic: if a spectator at another table catches the secret, the overall experience is going to be lessened for them, even if you don't perform the same effect for them when you get to their table. And if they happen to tip the method to the original spectator, their appreciation will drop as well.