When taking on a new user requires expensive onboarding: Require a credit card at signup (do a $0/$1 authorization) that you'll only charge after the trial.
Basically, if you have many "fake signups": 1/ you're attracting the wrong crowd. Fix your acquisition. 2/ these people are not "fake signups" but need more convincing to buy. Fix your onboarding/User Experience.
If you require a credit card at signup, you're turning away a good part of customers away who, at this point in time, don't know or trust you enough to give you payment details.
You can't boil everything down to a rule that applies to all businesses. Taking a credit card doesn't mean there's a forced continuity scam happening as that post seems to imply. You can make cancellation a one-click process, and send reminders before the trial ends (and should do so either way -- a good series of lifecycle e-mails are critical to converting trials). Lots of companies with pretty pristine reputations offer free trials that require a card, from Netflix to Amazon.