(This should answer deniser's post too)
That itself does not consitute use of trademark 'interflora', no, but I could still easily appear on a trademarked search if the consumer types 'interflora flowers' when one of my keywords is the phrase match 'flowers'
I'm sure a decent lawyer could argue that this would be a direct result of me not using trademarked negative matches, therefore leaving me liable.
Incidentally, for those not savvy with adwords/ppc (apologies if I sound patronising:
Phrase match keywords mean that as long as my keyword is part of of a query entered, my ad will be shown. ie, i have the phrase match keyword 'flowers', my ad could be shown when 'interflora flowers' 'buy flowers' or 'flower bouqets' is typed, et cetera.
Negative match keywords are keywords included in your campaign to ensure any search query which includes your negative match keyword will not show your ad. i.e. if 'interflora' is in my negative keyword list, my ad will not show for any search query that contains 'interflora'
So surely, as the manager of a ppc campaign with this knowledge, it would become my responsibility through use of negative match keywords to ensure my ad does not show for any trademarked term. Which, frankly, is unrealistic.