Registrars handle Whois Data Problem Reports (WDPR) differently for gTLDs - ccTLDs are a whole different topic entirely and not governed by such ICANN policies.
Some registrars give very little notice, such only several days, and then suspends the domain. While others send multiple reminders before taking action. Then some others simply make note of the complaint or even ignores it, and won't take any real action unless the complainant follow-ups / others complain about the same domain.
And the best registrars of all, in regards to security, from what I've read, if no response by the registrant, will simply update the whois, assuming the registrant field and/or customer data on file appears valid, to their own in-house email / privacy service, which is an effective work-around to satisfying ICANN Whois Data requirements - keeps the registrant happy and the domain working.
As for Namecheap ... suspending a domain after only 5 days is lousy service. Heck, so if someone goes on holiday, they come back and their domain is suspended / gone...
Also, NameCheap is primarily an eNom reseller - and hence, in many instances, it's actually eNom that's enforcing Whois Data Problem Reports for NameCheap customers - and that's an important detail, since eNom may potentially delete / resell such domains.
In short, NameCheap, when acting as an eNom reseller, can't guarantee what will or won't happen to a suspended domain - it's up to eNom what they'll do - possibly being what earns them the most money; reselling suspended domains.
Whois Data Problem Reports is a huge security hole (user passwords, registar-lock, Authcodes, etc are no protection) - some of the more savvy drop-catchers file such complaints when the need arises and then will work out a deal with the registrar to discreetly resell the domain to them.
Digressing a bit, but the above point is important to be aware of, because many WDPR complaints aren't motivated by spam or other issues, but rather simply by greed - people seeking to get other people's domains on the cheap.
Ron