I've only raced six races this season, so take this FWIW. I've been touched twice, in a 3/4 race (politely) and a mixed field Cat4/M50+ race (shoved hard by a Cat4). In the Masters and 1/2/3 races, no contact at all. I got myself into a double squeeze in the 1/2/3 race where two guys were fighting for the wheel in front of me, and there were just a few inches between me and the riders to either side. I could smell what they had for breakfast that morning. No contact.
I would much rather use my voice than take my hands off the bars unless it is absolutely necessary. If you pull the "pardon me, 'scuse me" deal, I might give you the wheel, depending on the state of the race at that time. Realize though that you may be doing all the work while towing me to the front.