For the record, the lock blocker was invented by Samson Mordan in 1830 - he called it the 'lock protector'. He used a bramah-type cylinder key mechanism of 7 sliders. Mordan had worked for Bramah, and after the lock patent expired S Mordan & Co. made high quality copies of the Bramah lock. Mordan ceased trading after their City of London works was blitzed in the winter of 1940-1, although the company was not wound up until 1946.
This device was to block the keyholes of locks, which at the time were warded or lever, the only cylinder locks there being at that period being Bramahs. Travellers, for example, did not always trust hotel locks then - as now, because we still have varieties of 'travel locks' for locking doors independently of the lock provided.