I can understand the WTP passengers sneaking in - having just been on a 3 class 777, the club loos are much close to WTP, rarely have a queue and/ or a trolley logjam stopping people getting back to their seats. That aside - there is a clear notice on the Club/WTP divider that toilets are at rear, so ignorance of which ones WTP are supposed to use is no excuse!

What annoyed me on both the out and return journeys was people from WT barging through the WTP cabin into club - some obviously in search of the loo, but on the way out, one gentleman in steerage was walking up and down umpteen times, sometimes with his iPad, sometimes without, but seemingly just going to visit a travel companion seated in club. The constant passage through the curtain was irritating to those of us in Row 12!

I'm a saddo who abides by the (unspoken) rules - I might grumble that the loo/ passenger ratio is ridiculous in WT/WTP, when compared to that in Club, and sometimes the WTP loos have long queues, especially those at the exit row where passengers have room to mill about without blocking the aisle