Wife got one for our upcoming baby. I think some may think its rude, especially the older women.
However, you wouldn't believe how many strangers just come up and start touching your baby. Unless you have them of course. Anywhere you go people just come up and want to touch a random baby that they don't even know. I know they're being nice but still.
nah, it's not rude. By all means keep that sign if you want to raise a weak child who will get sick all the time because you didn't want your unique snowflake to be exposed to germs in a world filled with germs.