Westminster magistrates' court heard on Tuesday that a "Billy No-Mates" would have had no chance of storming Fortnum & Mason.
The barb came as the trial of UK Uncut's anti-tax dodging activists continued, with the group accused of aggravated trespass over its occupation of the upmarket department store a year ago.
Prosecutor David Malone told protester Lewis Graham McNeill on Tuesday they had intended to thwart store security through "weight of numbers."
"No disrespect, but if you turned up with your flag - a Billy No-Mates - do you really think the security guards at the door would have let you in with your flag to go in and demonstrate, however well-meaning that demonstration was?
"To protest effectively you have to have your mates with you," Mr Malone said.
Convictions thus far in the case have relied on a ruling of joint enterprise that individual activists were part of a larger group, and that such a large group in a confined space constituted intimidation in and of itself.
But Mr McNeill contended that the protest's size reflected how many people were upset by tax avoidance. The large number simply made it "more of a reportable media grabbing event."
Mr Malone asked why the protesters could not have set up a stall or handed pamphlets to shoppers outside the store.
Police would have moved the group on immediately, Mr McNeill replied.
The trial is expected to conclude a year to the day after the arrests on March 26 2011, which saw nearly 150 protesters lured outside and handcuffed after occupying the store in protest at the role of tax avoidance in public-sector cuts.