I almost got bounced and I wasn't even dating anyone in the UK! I had printed off my bank statement, my credit card statement, a letter from my employer, and proof of enrollment at my university. (This was over spring break)
I was detained for several hours, questioned and requestioned and then questioned some more, finger printed twice, (did they think I had gone and changed my fingerprints?!?!?) and stuck in an extremely cold room with a some people who didn't seem all there (They kept yelling at and cussing out immigration officers).
I really was just coming to the UK as a tourist and to visit friends. I had done BUNAC in the past and visited twice before, once for a month and once for two weeks - all over a four year period.
I was finally let into the UK, I enjoyed my visit, and left on the day I had been stamped to leave.
I want to go back for another visit, but I've been kind of afraid to. I would never want to go through all of that again.