I respect people more when they say "Sorry, I don't know how to do that, can you show me?" than when they say "Sure" then do something incorrectly.
The company I work for runs a training program called TOPS. Basically, it is a short course for people who want to break into the AV industry, and at the end of the program, you are promoted to a "Level 1 AV Technician" within the companies internal ranking system. Sadly, a few Toppers come out of the program with the opinion that they know what they are doing, and are ready to handle shows, which is not the case (my personal opinion is that the TOPS program spits out graduates with a diploma in pushing cases and putting up drape lines who have at least 6 months of on the job before I would even consider them for babysitting a lecturn).
The Toppers that go far (and eventually move from Level 1 to Level 2, then Level 3 and finally to Technical Director (estimated time to TD rank is 10 years)) are the ones that admit to not knowing something and ask to be shown.
The Toppers that say they are ready to jump in the deep end and get given complex jobs and then do them badly, invariably become a member of the operations team, or leave the company..... Not sure if that is a good moral (be bad at what you do, and you will get moved to lower management)
So what I am trying to say is: If you are honest and up front about your abilities, yet show yourself to be willing to learn, you will NEVER taint your reputation. If you lie about your skills and don't live up to what you say you can do... well maybe there is a job in management for you... So it's not all bad...