Understandable, but we do it all the time in society – changing our natural reactions to less annoy others and to prevent unneeded attention from being drawn to us. I like to dance awkwardly to music, but I don’t do it in public, because I don’t want attention drawn to me. More to the point, we mimic what those around us worship with – in part for the sake of unity and cohesion. A person acting like a Pentecostal in a Presbyterian church, where even the people who raise up their hands for the Benediction look a bit out of place (or vice versa) would distract from the real focus, which is God, not the weird worship method our crazy neighbor is doing.
In addition, I should point out that the “annoying questions” bit was code speak for questions that would probably get a bit more personal and maybe even semi-hostile or worried for my soul. (Are you a Catholic? What are you doing that for? Don’t you know that’s a Catholic sign? Are you praying to God or Mary? Are you warding off demons?) Even if I myself could take these questions (I couldn’t – too shy), I wouldn’t want to worry my fellow Christians or draw them into some sin of malice or otherwise disturb them for the sake of a nice sign, harmless or no. (I think a similar precedent was set by Paul in 1 Corinthians 8.)
In all honesty, most of the Christians I know would probably think it a little weird, but otherwise be fine with it (I know a lot of really nice people). But ultimately I’m far too private to draw attention to myself and for the reasons above, I’m not convinced it would do my congregation any good and might cause a bit of harm amongst certain parties (hopefully not, but it might).
Does that help expand upon my thought process a bit more?