Gurbani says we should not break anyone's heart but at the same time a Gursikh who keeps a particular Rehat would not want to compromise it.
Some possible ways to follow a middle way in where unnecessary negativity and a clash could be avoided are..
1) Accept Degh and then discreetly give the Degh to the person next you (if you know them and they know and your Rehat) making sure its not made into a big scene. OR accept the Degh, discreetly keep Degh closed in your hands, and when you leave the Darbaar, you can either give the Degh to a family member or someone else who will happily eat it.
2) Another thing I have seen is that Gurmukhs just keep their eyes closed and immerse themselves in the Keertan, Katha or just keep 'mast' within themselves with eyes closed. Usually the person distributing Degh doesn't disturb them and moves on.
3) When Degh is being distributed, you could stand up and help out to distribute it yourself, or you could do another seva like Chaur Sahib or help tidy up the Darbaar Sahib.
4) Make Degh yourself according to Maryada and inspire and educate people through leading by example through sincerity, humility and pyaar.
Being rude and disrespectful should always being avoided. Elder Gursikhs always advise to keep Rehat discreet sometimes to avoid unneccessary negativity and for one to always keep a positive but humble and sincere attitude.
Vahegurooo