My partner and I play a mini NT (10-13 HCP) 1st NV. We have discussed and agreed that if we are a lot up towards the end of any sort of match (e.g. Swiss teams/pairs, knock-out teams) we will tend only to open the mini with a maximum, particularly love all at mps when -500 is fatal. To some extent, this agreement is 'just bridge', in the same way that most sensible players play very conservatively if they are a lot up. However, as this has come up a number of times and we've specifically talked about it I suppose it comes under the 'partnership agreement' heading.
So, how do we reveal this agreement to our opponents? Should our convention card say '10-13 1st NV, unless we have a big lead in the match in which case 12-13'? This is trickier in a short Swiss teams or pairs match, because it relies on both of us having the same opinion as to the state of the match without actually discussing it.
I am also not particularly looking forward to this conversation: Oppo: is that the mini? Me: yes, but it won't be 10-11 because we are hammering you 20-0. Oppo: I thought the match was fairly even Me: in that case maybe we should call the director [probably followed by my leaving the table while partner tells oppo whether he thinks we are winning 20-0 or not]