I feel that the field of countersignalling has applications to your concern.
http://www.theo.to/counter/counter.pdf
The fact that high types and low types will both send out the same signal (i.e. title engineer) should have no effect on you because unless you are a pleb there will be additional noisy information (your accent, your clothes and your modesty) that is too costly for the low types to imitate. Thus there will always exist a Bayesian Equilibrium where you are perfectly separated from the lows.
The fact that this bothers you only suggests to me and everyone else on the forum that you are a below average engineer and you are worried that when you graduate people will confuse you with a washing machine repair man. That's worrying - I suggest you sharpen up so such confusion will never occur.
Can I also just say that in my view, let the washing machine repairmen call themselves engineers and just don't ever call yourself an engineer. Think of something that makes you sound interesting. What Clarkson says about 'can you imagine going to a dinner party with the man who designed that?' is so true.
In my time at university I've only ever met one interesting engineer, and the reason he's interesting is because he's an utter genius who never attends any lectures yet can still pass the exams. For 99% of the people who study engineering they end up going to lectures 9-5 and then working on assignments every evening and that is enough to turn anyone into an incredibly boring person.
The most interesting people are those who spend a few years doing an arts degree, have oodles of free time and get to know themselves and spend the entire time interacting with other people. In that time social skills develop. That's why engineers have no social skills in my view, they simply haven't ever had the time to do it.
Being interesting, sociable and amusing is a skill that people learn just like any other, and if you choose to study something like Engineering or Physics unless you can do that without it taking up your time you'll never be cool.