People who are motivated to see a movie early are the same people who are likely to enjoy that movie. This makes it natural for movies to get rated very highly when they are first released. That's just natural.

If you forced people to photograph their ticket stub, I believe this could make the problem worse: mainly people who particularly loved the movie (or thought it was significantly worthy of comment) would be motivated enough to do that. You'll just collect the IMdB's 10s and 1s.

I know many people use the IMdB for their own record-keeping. These people would stop doing that if there was an administrative barrier that made it less convenient than a paper equivalent, e.g. writing in an address book. I strongly believe this makes their votes neutral/genuine compared to other survey methods.