Only had one nightmare on a hotel meet. Two big hotels just round the corner from each other and the nerves got the better of me and I completely screwed up and went to the wrong one.
Knocked on the room door...no answer, phoned the WG and said I'm outside the door, she said no you're not, then it dawned on me what I'd done. I just said, I'd got the wrong floor and then rushed over to the right hotel, a bit red-faced and flushed but only 5 mins late.
For the really nervous, the best hotels are Premier Inn with a Brewers Fayre next door, as you can usually go through the restaurant and then up some stairs to the hotel without even seeing the reception desk. Some WG's will book Premier Inn for that reason but most are not as clued-up as that unfortunately.