Beware of visitors bearing gifts.
Munster's greatest fear today may well be complacency once they viewed a Leinster team-sheet showing ten changes from the side that dismantled Northampton last weekend as the IRFU''s frustrating festive rules undermine the 22,600 Thomond Park sell-out..
Captain Peter O'Mahony will be more than aware that such is the strength of depth available to Leinster, the three-time European champions have already this season managed to see off a Dragons side despite not starting 19 of their star-studded international cast.
Then again, although this may not be Leinster as we know it, nor are Munster anything resembling the hapless Dragons.
Despite their loss in Leicester, Munster's seven-game winning run until that point demonstrated that this is a side who have added technical substance and poise to the obvious passions that have fired them since one fateful day in Paris.
Although Munster themselves have been forced into some change, the disruption is effectively minimal and, even though they themselves will have to release players for this week's trip to Connacht, one senses that Rassie Erasmus will be eyeing a festive double.
"They've always been - taking all the emotion aside - very well-coached, very well-disciplined, with a lot of good players who understand exactly what their game plan is and how to execute it," notes Leinster senior coach Stuart Lancaster.
"It is not just emotion that's driving the performances. It is quality coaches, quality players, who've got a real clear understanding of their game plan.
"Our challenge this week is to put pressure on that game plan and play the Leinster way in what's going to be an incredibly hostile and difficult environment for our players.
Mirroring Munster's league form, and the fact that both teams currently top the table on 37 points apiece - Munster lead by virtue of games won - Leinster have also not tasted defeat in eight matches since losing away to Scarlets in November when they were also missing the majority of their Irish internationals.
The stat that will really matter to Munster players and supporters is that which reflects a three-game winning streak in this fixture for the men in blue; offered a golden opportunity to wreak revenge, one feels certain they won't spurn this one.
Munster: S Zebo; D Sweetnam, J Taute, R Scannell, R O'Mahony; T Bleyendaal, C Murray; J Cronin, N Scannell, J Ryan; J Kleyn, D Ryan; P O'Mahony capt., T O'Donnell, CJ Stander. Reps: R Marshall, D Kilcoyne, S Archer, B Holland, J O'Donoghue, D Williams, F Saili, A Conway.
Leinster: Z Kirchner; R O'Loughlin, R Henshaw, B Daly; R Byrne, J Gibson-Park; C Healy, J Tracy, T Furlong, R Molony, M McCarthy, R Ruddock, D Leavy, J Conan.
Reps: R Strauss, P Dooley, M Bent, I Nagle, D Ryan, C Rock, N Reid, T Daly.
Ref: N Owens (WRU)